Jade

Jade is an ornamental stone. The term jade is applied to two different rocks that are made up of different silicate minerals. Nephrite jade consists of the calcium- and magnesium-rich amphibole mineral actinolite (aggregates of which also make up one form of asbestos). The rock called jadeitite consists almost entirely of jadeite, a sodium- and aluminium-rich pyroxene. The trade name Jadite [sic] is sometimes applied to translucent/opaque green glass.

The English word 'jade' is derived from the Spanish term piedra de ijada (first recorded in 1565) or 'loin stone', from its reputed efficacy in curing ailments of the loins and kidneys. 'Nephrite' is derived from lapis nephriticus, the Latin version of the Spanish piedra de ijada.[1]

Nephrite and jadeite were used by people from the prehistoric for similar purposes. Both are about the same hardness as quartz, and they are exceptionally tough. They are beautifully coloured and can be delicately shaped. Thus it was not until the 19th century that a French mineralogist determined that "jade" was in fact two different materials.

Among the earliest known jade artifacts excavated from prehistoric sites are simple ornaments with bead, button, and tubular shapes[2]. Additionally, jade was used for axe heads, knives, and other weapons. As metal-working technologies became available, the beauty of jade made it valuable for ornaments and decorative objects. Jade has a Mohs hardness of between 6.5 and 7.0,[3] so it can be worked with quartz or garnet sand, and polished with bamboo or even ground jade.

Nephrite can be found in a creamy white form (known in China as "mutton fat" jade) as well as in a variety of green colours, whereas jadeitite shows more colour variations, including dazzling blue, lavender-mauve, pink, and emerald-green colours. Of the two, jadeite is rarer, documented in fewer than 12 places worldwide. Translucent emerald-green jadeitite is the most prized variety, both now and historically. As "quetzal" jade, bright green jadeitite from Guatemala was treasured by Mesoamerican cultures, and as "kingfisher" jade, vivid green rocks from Burma became the preferred stone of post-1800 Chinese imperial scholars and rulers. Burma (Myanmar) and Guatemala are the principal sources of modern gem jadeitite, and Canada of modern lapidary nephrite. Nephrite jade was used mostly in pre-1800 China as well as in New Zealand, the Pacific Coast and Atlantic Coasts of North America, Neolithic Europe, and south-east Asia. In addition to Mesoamerica, jadeitite was used by Neolithic Japanese and European cultures.

Jade is the official gemstone of British Columbia, where it is found in large deposits in the Lillooet and Cassiar regions. It is also the official gemstone of the state of Alaska, found particularly in the Kobuk area. A two ton block of jade sits outside the Anchorage Visitor’s Center in downtown Anchorage, Alaska, mined from near Kobuk and donated to the city as a showpiece.

Zircon : Properties

Zircon is a remarkable mineral, if only for its almost ubiquitous presence in the crust of Earth. It is found in igneous rocks (as primary crystallization products), in metamorphic rocks and in sedimentary rocks (as detrital grains). Large zircon crystals are seldom abundant. Their average size, e.g. in granite rocks, is about 100–300 µm, but they can also grow to sizes of several centimeters, especially in pegmatites.

Owing to their uranium and thorium content, some zircons may undergo metamictization. This partially disrupts the crystal structure and explains the highly variable properties of zircon.

Properties
Zircon is a common accessory mineral and found worldwide. Noted occurrences include: in the Ural Mountains; Trentino, Monte Somma; and Vesuvius, Italy; Arendal, Norway; Sri Lanka, India; Thailand; Ratanakiri, Cambodia; at the Kimberley mines, Republic of South Africa; Madagascar; and in Canada in Renfrew County, Ontario, and Grenville, Quebec. In the United States: Litchfield, Maine; Chesterfield, Massachusetts; in Essex, Orange, and St. Lawrence Counties, New York; Henderson County, North Carolina; the Pikes Peak district of Colorado; and Llano County, Texas.

Thorite (ThSiO4) is an isostructural related mineral.

Zircon can come in red, brown, yellow, green, black, or colorless. The color of zircons below gem quality can be changed by heat treatment. Depending on the amount of heat applied, colorless, blue, and golden-yellow zircons can be made.

Zircon

Zircon
Zircon is a mineral belonging to the group of nesosilicates. Its chemical name is zirconium silicate and its corresponding chemical formula is ZrSiO4. Hafnium is almost always present in quantities ranging from 1 to 4%. The crystal structure of zircon is tetragonal crystal class. The natural color of zircon varies between colorless, yellow-golden, red, brown, and green. Colorless specimens that show gem quality are a popular substitute for diamond; these specimens are also known as "Matura diamond". It is not to be confused with cubic zirconia, a synthetic substance with a completely different chemical composition.

The name either derives from the Arabic word zarqun, meaning vermilion, or from the Persian zargun, meaning golden-colored. These words are corrupted into "jargoon", a term applied to light-colored zircons. Yellow zircon is called hyacinth, from a word of East Indian origin; in the Middle Ages all yellow stones of East Indian origin were called hyacinth, but today this term is restricted to the yellow zircons.

Zircon is regarded as the traditional birthstone for December.

General
Category Mineral
Chemical formula zirconium silicate ZrSiO4
Identification
Color brown, red, yellow, green, black, and colorless
Crystal habit dipyramidal prismatic
Crystal system Tetragonal; 4/m 2/m 2/m
Cleavage indistinct, two directions
Fracture Subconchoidal to uneven - brittle
Mohs Scale hardness 7.5
Luster Adamantine
Refractive index nω=1.967 - 2.015 nε=1.920 - 1.960
Birefringence δ=0.047 - 0.055
Streak White
Specific gravity 4.6–4.7
Fusibility Infusible
Solubility Insoluble
Other Characteristics Fluorescent and radioactive

Garnet : Garnet group endmember species

Garnet group endmember species
Almandine
Almandine in gneissic rock

Almandine, sometimes incorrectly called almandite, is the modern gem known as carbuncle (though originally almost any red gemstone was known by this name). The term "carbuncle" is derived from the Latin meaning "little spark." The name Almandine is a corruption of Alabanda, a region in Asia Minor where these stones were cut in ancient times. Chemically, almandine is an iron-aluminium garnet with the formula Fe3Al2(SiO4)3; the deep red transparent stones are often called precious garnet and are used as gemstones (being the most common of the gem garnets). Almandine occurs in metamorphic rocks like mica schists, associated with minerals such as staurolite, kyanite, andalusite, and others. Almandine has nicknames of Oriental garnet, almandine ruby, and carbuncle.

Pyrope
Pyrope, from the Latin pyropos, means similar to fire. It is red in color and chemically a magnesium aluminium silicate with the formula Mg3Al2(SiO4)3, though the magnesium can be replaced in part by calcium and ferrous iron. The color of pyrope varies from deep red to almost black. Transparent pyropes are used as gemstones.

A variety of pyrope from Macon County, North Carolina is a violet-red shade and has been called rhodolite, from the Greek meaning "a rose." In chemical composition it may be considered as essentially an isomorphous mixture of pyrope and almandite, in the proportion of two parts pyrope to one part almandite. Pyrope has tradenames some of which are misnomers; Cape ruby, Arizona ruby, California ruby, Rocky Mountain ruby, and Bohemian garnet from the Czech Republic. Another intriguing find is the blue color-change garnets from Madagascar, a pyrope spessartine mix. The color of these blue garnets is not like sapphire blue in subdued daylight but more reminiscent of the grayish blues and greenish blues sometimes seen in spinel However in white LED light the color is equal to the best corn flower blue sapphire or D block tanzanite this is due to the blue garnets ability to absorb the yellow component of the emitted light.

Pyrope is an indicator mineral for high pressure rocks. The garnets from mantle derived rocks, peridotites and eclogites, commonly contain a pyrope variety.

Spessartine
Spessartine or incorrectly spessartite is manganese aluminium garnet, Mn3Al2(SiO4)3. Its name is derived from Spessart in Bavaria. It occurs most often in granite pegmatite and allied rock types and in certain low grade metamorphic phyllites. Spessartine of a beautiful orange-yellow is found in Madagascar (see Mandarin garnet). Violet-red spessartines are found in rhyolites in Colorado and Maine.

Andradite
Andradite is a calcium-iron garnet, Ca3Fe2(SiO4)3, is of variable composition and may be red, yellow, brown, green or black. The recognized varieties are topazolite (yellow or green), demantoid (green) and melantite (black). Andradite is found both in deep-seated igneous rocks like syenite as well as serpentines, schists, and crystalline limestone. Demantoid has been called the "emerald of the Urals" from its occurrence there, and is one of the most prized of garnet varieties. Topazolite is a golden yellow variety and melanite is a black variety.

Grossular
Grossular is a calcium-aluminium garnet with the formula Ca3Al2(SiO4)3, though the calcium may in part be replaced by ferrous iron and the aluminium by ferric iron. The name grossular is derived from the botanical name for the gooseberry, grossularia, in reference to the green garnet of this composition that is found in Siberia. Other shades include cinnamon brown (cinnamon stone variety), red, and yellow. Because of its inferior hardness to zircon, which the yellow crystals resemble, they have also been called hessonite from the Greek meaning inferior. Grossular is found in contact metamorphosed limestones with vesuvianite, diopside, wollastonite and wernerite.

One of the most sought after varieties of gem garnet is the fine green grossular garnet from Kenya and Tanzania called tsavorite. This garnet was discovered in the 1960s in the Tsavo area of Kenya, from which the gem takes its name.

Uvarovite
Uvarovite is a calcium chromium garnet with the formula Ca3Cr2(SiO4)3. This is a rather rare garnet, bright green in color, usually found as small crystals associated with chromite in peridotite, serpentinite, and kimberlites. It is found in crystalline marbles and schists in the Ural mountains of Russia and Outokumpu, Finland.

Garnet

Garnet
Garnet is a group of minerals that have been used since the Bronze Age as gemstones and abrasives. Garnets are most often seen in red, but are available in a wide variety of colors spanning the entire spectrum. The name "garnet" comes from the Latin granatus ("grain"), possibly a reference to the Punica granatum ("pomegranate"), a plant with red seeds similar in shape, size, and color to some garnet crystals.

Six common species of garnet are recognized based on their chemical composition. They are pyrope, almandine, spessartite, grossular (varieties of which are hessonite or cinnamon-stone and tsavorite), uvarovite and andradite. The garnets make up two solid solution series; 1. pyrope-almandine-spessarite and 2. uvarovite-grossular-andradite.

General
Category nesosilicates
Chemical formula The general formula X3Y2(SiO4)3
Identification
Color virtually all colors
Crystal habit rhombic dodecahedra or cubic
Crystal system Isometric
Cleavage None
Fracture conchoidal to uneven
Mohs Scale hardness 6.0 - 7.5
Luster vitreous to resinous
Polish luster vitreous to subadamantine [1]
Refractive index 1.72 - 1.94
Optical Properties Single refractive, often anomalous double refractive [1]
Birefringence None
Pleochroism only in certain rare varieties
Streak White
Specific gravity 3.1 - 4.3
Major varieties
Pyrope Mg3Al2Si3O12
Almandine Fe3Al2Si3O12
Spessartite Mn3Al2Si3O12
Andradite Ca3Fe2Si3O12
Grossular Ca3Al2Si3O12
Uvarovite Ca3Cr2Si3O12

Sapphire : Synthetic sapphire

Synthetic sapphire
Synthetic sapphire crystals can be grown in cylindrical crystal boules of large size, up to many inches in diameter. As well as gemstone applications there are many other uses:

The first ever laser produced was based on the ruby, the red variety of corundum. While this laser has few applications, the Ti-sapphire laser is popular due to the relatively rare ability to tune the laser wavelength in the red-to-near infrared region of the electromagnetic spectrum. It can also be easily modelocked. In these lasers, a synthetically produced sapphire crystal with chromium or titanium impurities is irradiated with intense light from a special lamp, or another laser, to create stimulated emission.

Pure sapphire boules can be sliced into wafers and polished to form transparent crystal slices. Such slices are used as watch faces in high quality watches, as the material's exceptional hardness makes the face resistant to scratching. Since sapphire ranks a 9 on the Mohs Scale, owners of such watches should still be careful to avoid exposure to diamond jewelry, and should avoid striking their watches against artificial stone and simulated stone surfaces. Such surfaces often contain materials including silicon carbide, which, like diamond, are harder than sapphire and thus capable of causing scratches (Scheel 2003).

Sapphire is highly transparent at wavelengths of light between 170 nm to 5.3 μm, as well as being five times stronger than glass. This leads to use of synthetic sapphire windows in high pressure chambers for spectroscopy.

Wafers of single crystal sapphire are also used in the semiconductor industry as a substrate for the growth of gallium nitride based devices.
Cermax Xenon arc lamp with synthetic sapphire output window

One type of Xenon Arc Lamp known as Cermax (original brand name - generically known as a ceramic body xenon lamp) use sapphire output windows that are doped with various other elements to tune their emission. In some cases, the UV emitted from the lamp during operation causes a blue glow from the window after the lamp is turned off. It is approximately the same color as Cherenkov radiation but is caused by simple phosphorescence.

sapphire : Natural sapphire

Natural sapphire
Although blue is considered the normal color for sapphires, they can be found across a full range of spectral colors as well as brown, colorless, grey and black. Those other than blue in color are considered fancy color sapphires. Some natural sapphires can be found as completely transparent, or "white." White sapphires usually come out of the ground as light grey or brown and are then heated to make them clear. However, in very rare circumstances they will be found in a clear state.

Blue sapphire
Various shades of blue [dark and light] result from titanium and iron substitutions in the aluminum oxide crystal lattice. Some stones are not well saturated and show tones of gray. It is common practice to bake natural sapphires to improve or enhance color. This is usually done by heating the sapphires to temperatures of up to 1800 °C for several hours, or by heating in a nitrogen deficient atmosphere oven for seven days or more. On magnification, the silk due to included rutile needles are often visible. If the needles are unbroken, then the stone was not heated; if the silk is not visible then the stone was heated adequately. If the silk is partially broken, then a process known as low tube heat may have been used. Low tube heat is the process whereby the rough stone is heated to 1300 °C over charcoal for 20 to 30 minutes. This removes gray or brown in the stone and improves color saturation.

Fancy color sapphire
Purple sapphires are lower in price than blue ones. These stones contain the trace element vanadium and come in a variety of shades. Yellow and green sapphires have traces of iron that gives them their color. Pink sapphires have a trace of the element chromium and the deeper the color pink the higher their monetary value as long as the color is going toward the red of rubies. Sapphires also occur in shades of orange and brown, and colorless sapphires are sometimes used as diamond substitutes in jewelry. Salmon-color padparadscha sapphires are orangy-pink, pinkish-orange or pink-orange in color, which often fetch higher prices than many of even the finest blue sapphires. The word 'padparadscha' is Sinhalese for 'lotus flower'. Recently many sapphires of this color have appeared on the market as a result of a new treatment method called "bulk diffusion".[

Color change sapphire
Color shift sapphires are blue in outdoor light and purple under [incandescent] indoor light. Color changes may also be pink in daylight to greenish under fluorescent light. Some stones shift color well and others only partially, in that some stones go from blue to bluish purple. Such color-change sapphires are widely sold as “lab” or “synthetic” alexandrite, which is accurately called an alexandrite simulant (also called alexandrium) since the latter is actually a type of chrysoberyl---an entirely different substance whose pleochroism is different and much more pronounced than color-change corundum (sapphire).

Star sapphire
A star sapphire is a type of sapphire that exhibits a star-like phenomenon known as asterism. Star sapphires contain intersecting needle-like inclusions (often the mineral rutile, a mineral composed primarily of titanium dioxide ) that cause the appearance of a six-rayed 'star'-shaped pattern when viewed with a single overhead light source.

The value of a star sapphire depends not only on the carat weight of the stone but also the body color, visibility and intensity of the asterism.

Treatments
Some sapphires are heat-treated or otherwise enhanced to improve their appearance and color, though some people object to such practices and prefer natural untreated stones. Heat treatments tend to improve the sapphire's color and clarity, and it is unusual to find un-heated stones for sale. Diffusion treatments are somewhat more controversial as they are used to add elements to the sapphire for the purpose of improving colors.

Mining
Sapphires are mined from alluvial deposits or from primary underground workings. The finest specimens are mined in Sri Lanka; both the Logan sapphire and the Star of Bombay originate from Sri Lankan mines. Sapphires are also mined in Australia, Madagascar, Thailand and Myanmar. Madagascar leads the world in sapphire production (as of 2007) specifically in and around the city of Ilakala. Prior to Ilakala, Australia was the largest producer of sapphires (as of 1987). Ilakala is prone to violence, but sapphires are found everywhere including on the ground and in the river mud. Pakistan, Afghanistan, India, Tanzania and Kenya also produce sapphires. The US state of Montana has produced sapphires from both the El Dorado Bar and Spokane Bar deposit near Helena. Well-known for their intense, pure blue color, yogo sapphires are found in Yogo Gulch, near Utica, Montana. Gem grade sapphires and rubies are also found in and around Franklin, North Carolina, USA. Several mines are open to the public.

Sapphire

Sapphire
Sapphire refers to gem varieties of the mineral corundum, an aluminum oxide (Al2O3), when it is a color other than red. It can be found naturally or manufactured in large crystal boules for varied applications, including infrared optical components, watch faces, high-durability windows, and wafers for the deposition of semiconductors such as GaN nanorods.

The mineral corundum consists of pure aluminum oxide. Trace amounts of other elements such as iron, titanium and chromium give corundum their blue, yellow, pink, purple, orange or greenish color. Sapphire includes any gemstone quality varieties of the mineral corundum except the fully saturated red variety, which is instead known as ruby, and the pinkish-orange variety known as padparadscha.

General
Category Mineral Variety
Chemical formula aluminum oxide, Al2O3
Identification
Color Every color except red (which is ruby)
Crystal habit massive and granular
Crystal system Trigonal
Cleavage None
Fracture Conchoidal, splintery
Mohs Scale hardness 9.0
Luster Vitreous
Refractive index 1.762-1.778
Pleochroism Strong
Streak White
Specific gravity 3.95-4.03
Fusibility infusible
Solubility insoluble
Other Characteristics Coefficient of thermal expansion 5e-6–6.6e-6/K

Emerald : Emerald in different cultures and Emerald lore

Emerald in different cultures and Emerald lore

Emerald is regarded as the traditional birthstone for May, as well as the traditional gemstone for the astrological signs of Taurus and Cancer. One of the more quaint anecdotes on emeralds was by the 16th century historian Brantome, who referred to the many impressive emeralds the Spanish under Cortez had brought back to Europe from Latin America. On one of Cortez most famous emeralds he had the text engraved Inter Natos Mulierum non sur-rexit mayor (Among them borne of woman there hath not arisen a greater Man. XI, 11) which referred to John the Baptist. Brantome considered engraving such a beautiful and simple product of nature sacrilegious and considered this act the cause for Cortez loss of an extremely precious pearl (to which he dedicated a work A beautiful and incomparable pearl) and even for the death of King Charles IX who died soon after.

High Priest Breastplate

In Exodus chapters 28 and 39, a number of precious stones are mentioned to be placed in the High Priest's Breastplate, representing the different tribes of Israel. This is generally considered to be (one of) the origin(s) of our present day tradition of birthstones.

According to Rebbenu Bachya, and the King James Version, the Hebrew word Nofech in Exodus 28:18 means Emerald, and was the stone on the Hoshen representing the tribe of Judah. However, the Septuagint translates the word as Anthrax, meaning coal, probably in reference to the colour of burning coal, and therefore many rabbinical sources, and most scholars, consider Nofech to mean a red garnet – traditionally called a carbuncle, which happens to be the Vulgate's translation of the word. There is a wide range of views among traditional sources about which tribe the stone refers to.

There are many complexities to identifying the Emerald as being the third stone or perhaps another stone on the breast plate. Multiple translations of the bible have created confusion about the nomenclature of the different stones. Another important fact is that in actuality there are 2 different breastplates made within a period of 800 years, and where it is assumed the first breastplate did not carry an Emerald but a green Felspar, and a real Emerald in the second breastplate. Finally the 12th stone in the Breastplate (which in the original text was actually listed as the 6th stone) has more generally been identified as Beryl which was already included in the group of stones generally referred to as Smaragdus by Theophrastus in the Greek era. . Further unreferenced claims regarding the possibility of what gemstone the Emerald could really have been include Jasper, and even Rubies.

In some cultures, the emerald is the traditional gift for the 55th wedding anniversary. It is also used as a 20th and 35th wedding anniversary stone.

Emerald : Synthetic emerald

Synthetic emerald
Emerald is a rare and valuable gemstone and, as such, it has provided the incentive for developing synthetic emeralds. Both hydrothermal and flux-growth synthetics have been produced, and a method has been developed for producing an emerald overgrowth on colorless beryl. The first commercially successful emerald synthesis process was that of Carroll Chatham. Because Chatham's emeralds do not have any water and contain traces of vanadate, molybdenum and vanadium, a lithium vanadate flux process is probably involved. The other large producer of flux emeralds is Pierre Gilson Sr., which has been on the market since 1964. Gilson's emeralds are usually grown on natural colorless beryl seeds which become coated on both sides. Growth occurs at the rate of 1 mm per month and a typical seven-month growth run produces emerald crystals of 7 mm of thickness (Nassau, K. Gems Made By Man, 1980).

Hydrothermal synthetic emeralds have been attributed to IG Farben, Nacken, Tairus and others, but the first satisfactory commercial product was that of Johann Lechleitner of Inbruck, Austria, which appeared on the market in the 1960s. These stones were initially sold under the names "Emerita" and "Symeralds", and they were grown as a thin layer of emerald on top of natural colorless beryl stones. Although not much is known about the original process, it is assumed that Leichleitner emeralds were grown in acid conditions. Later, from 1965 to 1970, the Linde Division of Union Carbide produced completely synthetic emeralds by hydrothermal synthesis. According to their patents (US3,567,642 and US3,567,643), acidic conditions are essential to prevent the chromium (which is used as the colorant) from precipitating. Also, it is important that the silicon containing nutrient be kept away from the other ingredients in order to prevent nucleation and confine growth to the seed crystals. Growth occurs by a diffusion-reaction process, assisted by convection. Typical growth conditions include pressures of 700-1400 bars at temperatures of 500 to 600 °C with a temperature gradient of 10 to 25 °C. Growth rates as fast as 1/3 mm per day can be attained[citation needed]

Luminescence in ultraviolet light is considered a supplementary test when making a natural vs. synthetic determination, as many, but not all, natural emeralds are inert to ultraviolet light. Many synthetics are also UV inert.

Synthetic emeralds are often referred to as "created", as their chemical and gemological composition is the same as their natural counterparts. The U.S. Federal Trade Commission (FTC) has very strict regulations as to what can and what cannot be called "synthetic" stone. The FTC says: "§ 23.23(c) It is unfair or deceptive to use the word "laboratory-grown," "laboratory-created," "[manufacturer name]-created," or "synthetic" with the name of any natural stone to describe any industry product unless such industry product has essentially the same optical, physical, and chemical properties as the stone named."

Wispy veil-like inclusions are common in flux-grown synthetic emeralds.

Emerald

Emerald
Emeralds are a variety of the mineral beryl (Be3Al2(SiO3)6,) colored green by trace amounts of chromium and sometimes vanadium.. Beryl has a hardness of 7.5 - 8 on the 10 point Mohs scale of mineral hardness. Most emeralds are highly included, so their brittleness (resistance to breakage) is classified as generally poor. The origin of the word "emerald" is said to be a Sanskrit word meaning "green".

General
Category Beryl variety
Chemical formula Beryllium aluminium silicate with chromium, Be3Al2(SiO3)6::Cr
Identification
Color Green
Crystal habit Hexagonal Crystals
Crystal system Hexagonal
Cleavage Poor Basal Cleavage (Seldom Visible)
Fracture Conchoidal
Mohs Scale hardness 7.5 - 8.0
Luster Vitreous
Refractive index 1.576 - 1.582
Pleochroism Distinct, Blue-Green/Yellow-Green
Streak White
Specific gravity 2.70 - 2.78

Diamond : The diamond industry

The diamond industry
The diamond industry can be broadly separated into two basically distinct categories: one dealing with gem-grade diamonds and another for industrial-grade diamonds. While a large trade in both types of diamonds exists, the two markets act in dramatically different ways.

Gem diamond industry
Main article: Diamond (gemstone)

A large trade in gem-grade diamonds exists. Unlike precious metals such as gold or platinum, gem diamonds do not trade as a commodity: there is a substantial mark-up in the sale of diamonds, and there is not a very active market for resale of diamonds. One hallmark of the trade in gem-quality diamonds is its remarkable concentration: wholesale trade and diamond cutting is limited to a few locations. 92% of diamond pieces cut in 2003 were in Surat, Gujarat, India. Other important centers of diamond cutting and trading are Antwerp, London, New York, Tel Aviv, Amsterdam. A single company—De Beers—controls a significant proportion of the trade in diamonds. They are based in Johannesburg, South Africa and London, England.

The production and distribution of diamonds is largely consolidated in the hands of a few key players, and concentrated in traditional diamond trading centers. The most important being Antwerp, where 80% of all rough diamonds, 50% of all cut diamonds and more than 50% of all rough, cut and industrial diamonds combined are handled.[citation needed] This makes Antwerp the de facto 'world diamond capital'. New York, however, along with the rest of the United States, is where almost 80% of the world's diamonds are sold, including at auction. Also, the largest and most unusually shaped rough diamonds end up in New York. The De Beers company, as the world's largest diamond miner holds a clearly dominant position in the industry, and has done so since soon after its founding in 1888 by the British imperialist Cecil Rhodes. De Beers owns or controls a significant portion of the world's rough diamond production facilities (mines) and distribution channels for gem-quality diamonds. The company and its subsidiaries own mines that produce some 40 percent of annual world diamond production. At one time it was thought over 80 percent of the world's rough diamonds passed through the Diamond Trading Company (DTC, a subsidiary of De Beers) in London, but presently the figure is estimated at less than 50 percent.

The De Beers diamond advertising campaign is acknowledged as one of the most successful and innovative campaigns in history. N. W. Ayer & Son, the advertising firm retained by De Beers in the mid-20th century, succeeded in reviving the American diamond market and opened up new markets, even in countries where no diamond tradition had existed before. N.W. Ayer's multifaceted marketing campaign included product placement, advertising the diamond itself rather than the De Beers brand, and building associations with celebrities and royalty. This coordinated campaign has lasted decades and continues today; it is perhaps best captured by the slogan "a diamond is forever".

Further down the supply chain, members of The World Federation of Diamond Bourses (WFDB) act as a medium for wholesale diamond exchange, trading both polished and rough diamonds. The WFDB consists of independent diamond bourses in major cutting centres such as Tel Aviv, Antwerp, Johannesburg and other cities across the USA, Europe and Asia.

In 2000, the WFDB and The International Diamond Manufacturers Association established the World Diamond Council to prevent the trading of diamonds used to fund war and inhumane acts.

WFDB's additional activities also include sponsoring the World Diamond Congress every two years, as well as the establishment of the International Diamond Council (IDC) to oversee diamond grading.

Industrial diamond industry

The market for industrial-grade diamonds operates much differently from its gem-grade counterpart. Industrial diamonds are valued mostly for their hardness and heat conductivity, making many of the gemological characteristics of diamond, including clarity and color, mostly irrelevant. This helps explain why 80% of mined diamonds (equal to about 100 million carats or 20,000 kg annually), unsuitable for use as gemstones and known as bort, are destined for industrial use. In addition to mined diamonds, synthetic diamonds found industrial applications almost immediately after their invention in the 1950s; another 3 billion carats (600 metric tons) of synthetic diamond is produced annually for industrial use.

The dominant industrial use of diamond is in cutting, drilling, grinding, and polishing. Most uses of diamonds in these technologies do not require large diamonds; in fact, most diamonds that are gem-quality except for their small size, can find an industrial use. Diamonds are embedded in drill tips or saw blades, or ground into a powder for use in grinding and polishing applications. Specialized applications include use in laboratories as containment for high pressure experiments (see diamond anvil), high-performance bearings, and limited use in specialized windows.

With the continuing advances being made in the production of synthetic diamonds, future applications are beginning to become feasible. Garnering much excitement is the possible use of diamond as a semiconductor suitable to build microchips from, or the use of diamond as a heat sink in electronics.

Diamond supply chain
See also: List of diamond mines

The diamond supply chain is controlled by a limited number of powerful businesses, and is also highly concentrated in a small number of locations around the world.

Mining, Sources and Production

Only a very small fraction of the diamond ore consists of actual diamonds. The ore is crushed, during which care has to be taken in order to prevent larger diamonds from being destroyed in this process and subsequently the particles are sorted by density. Today, diamonds are located in the diamond-rich density fraction with the help of X-ray fluorescence, after which the final sorting steps are done by hand. Before the use of X-rays became commonplace, the separation was done with grease belts; diamonds have a stronger tendency to stick to grease than the other minerals in the ore.

Historically diamonds were known to be found only in alluvial deposits in southern India. India led the world in diamond production from the time of their discovery in approximately the 9th century BCE to the mid-18th century AD, but the commercial potential of these sources had been exhausted by the late 18th century and at that time India was eclipsed by Brazil where the first non-Indian diamonds was found in 1725.

Diamond production of primary deposits (kimberlites and lamproites) only started in the 1870's after the discovery of the Diamond fields in South Africa. Production has increased over time and now an accumulated total of 4.5 billion carats have been mined since that date. Interestingly 20% of that amount has been mined in the last 5 years alone and during the last ten years, 9 new mines have started production while 4 more are awaiting opening soon. Most of these mines are located in Canada, Zimbabwe, Angola, and one in Russia.

While no commercial diamond production exists in the US, Arkansas and Colorado are the only states to have a verifiable source of diamonds.

Today, most commercially viable diamond deposits are in Russia, Botswana, Australia and the Democratic Republic of Congo.[23] In 2005, Russia produced almost one-fifth of the global diamond output, reports the British Geological Survey. Australia boasts the richest diamondiferous pipe with production reaching peak levels of 42 Mct per year in the 1990's

There are also commercial deposits being actively mined in the Northwest Territories of Canada, Siberia (mostly in Yakutia territory, for example Mir pipe and Udachnaya pipe), Brazil, and in Northern and Western Australia. Diamond prospectors continue to search the globe for diamond-bearing kimberlite and lamproite pipes.

Blood diamonds
Main article: Blood diamond

In some of the more politically unstable central African and west African countries, revolutionary groups have taken control of diamond mines, using proceeds from diamond sales to finance their operations. Diamonds sold through this process are known as conflict diamonds or blood diamonds. Major diamond trading corporations continue to fund and fuel these conflicts by doing business with armed groups. In response to public concerns that their diamond purchases were contributing to war and human rights abuses in central Africa and West Africa, the United Nations, the diamond industry and diamond-trading nations introduced the Kimberley Process in 2002, which is aimed at ensuring that conflict diamonds do not become intermixed with the diamonds not controlled by such rebel groups, by providing documentation and certification of diamond exports from producing countries to ensure that the proceeds of sale are not being used to fund criminal or revolutionary activities. Although the Kimberley Process has been moderately successful in limiting the number of conflict diamonds entering the market, conflict diamonds smuggled to market continue to persist to some degree (approx. 2–3% of diamonds traded today are possible conflict diamonds[24]). According to the 2006 book The Heartless Stone, two major flaws still hinder the effectiveness of the Kimberley Process: the relative ease of smuggling diamonds across African borders and giving phony histories, and the violent nature of diamond mining in nations which are not in a technical state of war and whose diamonds are therefore considered "clean."

The Canadian Government has setup a body known as Canadian Diamond Code of Conduct to help authenticate Canadian Diamonds. This is a very stringent tracking system of diamonds and helps protect the 'conflict free' label of Canadian diamonds.

Currently, gem production totals nearly 30 million carats (6,000 kg) of cut and polished stones annually, and over 100 million carats (20,000 kg) of mined diamonds are sold for industrial use each year, as are about 100,000 kg of synthesized diamond.

Distribution

The Diamond Trading Company, or DTC, is a subsidiary of De Beers and markets rough diamonds produced both by De Beers mines and other mines from which it purchases rough diamond production. Once purchased by sightholders, diamonds are cut and polished in preparation for sale as gemstones. The cutting and polishing of rough diamonds is a specialized skill that is concentrated in a limited number of locations worldwide. Traditional diamond cutting centers are Antwerp, Amsterdam, Johannesburg, New York, and Tel Aviv. Recently, diamond cutting centers have been established in China, India, and Thailand. Cutting centers with lower cost of labor, notably Surat in Gujarat, India, handle a larger number of smaller carat diamonds, while smaller quantities of larger or more valuable diamonds are more likely to be handled in Europe or North America. The recent expansion of this industry in India, employing low cost labor, has allowed smaller diamonds to be prepared as gems in greater quantities than was previously economically feasible.

Diamonds which have been prepared as gemstones are sold on diamond exchanges called bourses. There are 26 registered diamond bourses. This is the final tightly controlled step in the diamond supply chain; wholesalers and even retailers are able to buy relatively small lots of diamonds at the bourses, after which they are prepared for final sale to the consumer. Diamonds can be sold already set in jewelry, or as is increasingly popular, sold unset ("loose"). According to the Rio Tinto Group, in 2002 the diamonds produced and released to the market were valued at US$9 billion as rough diamonds, US$14 billion after being cut and polished, US$28 billion in wholesale diamond jewelry, and retail sales of US$57 billion.

Diamond : Natural history

Natural history
Formation

The formation of natural diamond requires very specific conditions. Diamond formation requires exposure of carbon-bearing materials to high pressure, ranging approximately between 45 and 60 kilobars,[12] but at a comparatively low temperature range between approximately 1652–2372 °F (900–1300 °C). These conditions are known to be met in two places on Earth; in the lithospheric mantle below relatively stable continental plates, and at the site of a meteorite strike.

Diamonds formed in cratons

The conditions for diamond formation to happen in the lithospheric mantle occur at considerable depth corresponding to the aforementioned requirements of temperature and pressure. These depths are estimated to be in between 140–190 kilometers (90–120 miles)[12][7] though occasionally diamonds have crystallized at depths of 300-400 km (180-250 miles) as well.[13] The rate at which temperature changes with increasing depth into the Earth varies greatly in different parts of the Earth. In particular, under oceanic plates the temperature rises more quickly with depth, beyond the range required for diamond formation at the depth required.[12] The correct combination of temperature and pressure is only found in the thick, ancient, and stable parts of continental plates where regions of lithosphere known as cratons exist.[12] Long residence in the cratonic lithosphere allows diamond crystals to grow larger.

Through studies of carbon isotope ratios (similar to the methodology used in carbon dating, except with the stable isotopes C-12 and C-13), it has been shown that the carbon found in diamonds comes from both inorganic and organic sources. Some diamonds, known as harzburgitic, are formed from inorganic carbon originally found deep in the Earth's mantle. In contrast, eclogitic diamonds contain organic carbon from organic detritus that has been pushed down from the surface of the Earth's crust through subduction (see plate tectonics) before transforming into diamond.[7] These two different source carbons have measurably different 13C:12C ratios. Diamonds that have come to the Earth's surface are generally very old, ranging from under 1 billion to 3.3 billion years old.

Diamonds occur most often as euhedral or rounded octahedra and twinned octahedra known as macles or maccles. As diamond's crystal structure has a cubic arrangement of the atoms, they have many facets that belong to a cube, octahedron, rhombicosidodecahedron, tetrakis hexahedron or disdyakis dodecahedron. The crystals can have rounded off and unexpressive edges and can be elongated. Sometimes they are found grown together or form double "twinned" crystals grown together at the surfaces of the octahedron. These different shapes and habits of the diamonds result from differing external circumstances. Diamonds (especially those with rounded crystal faces) are commonly found coated in nyf, an opaque gum-like skin.

Diamond

Diamond
Diamond is an allotrope of carbon. It is the hardest known natural material and the third-hardest known material after aggregated diamond nanorods and ultrahard fullerite. Its hardness and high dispersion of light make it useful for industrial applications and jewelry.

Diamonds are specifically renowned as a material with superlative physical qualities; they make excellent abrasives because they can be scratched only by other diamonds, Borazon, ultrahard fullerite, or aggregated diamond nanorods, which also means they hold a polish extremely well and retain their lustre. Approximately 130 million carats (26,000 kg) are mined annually, with a total value of nearly USD $9 billion, and about 100,000 kg are synthesized annually.[2]

The name diamond derives from the ancient Greek adamas (αδάμας; “invincible”). They have been treasured as gemstones since their use as religious icons in ancient India and usage in engraving tools also dates to early human history.[3][4] Popularity of diamonds has risen since the 19th century because of increased supply, improved cutting and polishing techniques, growth in the world economy, and innovative and successful advertising campaigns. They are commonly judged by the “four Cs”: carat, clarity, color, and cut.

Roughly 49% of diamonds originate from central and southern Africa, although significant sources of the mineral have been discovered in Canada, India, Russia, Brazil, and Australia. They are mined from kimberlite and lamproite volcanic pipes, which brought to the surface the diamond crystals from deep in the Earth where the high pressure and temperature enables the formation of the crystals. The mining and distribution of natural diamonds are subjects of frequent controversy such as with concerns over the sale of conflict diamonds (aka blood diamonds) by African paramilitary groups.

General
Category Native Minerals
Chemical formula C
Identification
Molecular Weight 12.01 u
Color Typically yellow, brown or gray to colorless. Less often in blue, green, black, translucent white, pink, violet, orange, purple and red.
Crystal habit Octahedral
Crystal system Isometric-Hexoctahedral (Cubic)
Cleavage 111 (perfect in four directions)
Fracture Conchoidal - step like
Mohs Scale hardness 10
Luster Adamantine
Polish luster Adamantine
Refractive index 2.4175–2.4178
Optical Properties Singly Refractive
Birefringence none
Dispersion .044
Pleochroism none
Ultraviolet fluorescence colorless to yellowish stones - inert to strong in long wave, and typically blue. Weaker in short wave.
Absorption spectra In pale yellow stones a 415.5 nm line is typical. Irradiated and annealed diamonds often show a line around 594 nm when cooled to low temperatures.
Streak White
Specific gravity 3.52 (+/- .01)
Density 3.5-3.53
Diaphaneity Transparent to subtransparent to translucent

Material properties
A diamond is a transparent crystal of tetrahedrally bonded carbon atoms and crystallizes into the face centered cubic diamond lattice structure. Diamonds have been adapted for many uses because of the material's exceptional physical characteristics. Most notable are its extreme hardness, its high dispersion index, and extremely high thermal conductivity (900 – 2320 W/m K), with a melting point of 3820 K (3547 °C / 6420 °F) and a boiling point of 5100 K (4827 °C / 8720 °F).[5] Naturally occurring diamonds have a density ranging from 3.15 to 3.53 g/cm³, with very pure diamond typically extremely close to 3.52 g/cm³.

Hardness

Diamond is the hardest natural material known to man; hardness is defined as resistance to scratching. Diamond has a hardness of 10 (hardest) on Mohs scale of mineral hardness[7]. Diamond's hardness has been known since antiquity, and is the source of its name.

The hardest diamonds in the world are from the New England area in New South Wales, Australia. These diamonds are generally small, perfect to semiperfect octahedra, and are used to polish other diamonds. Their hardness is considered to be a product of the crystal growth form, which is single stage growth crystal. Most other diamonds show more evidence of multiple growth stages, which produce inclusions, flaws, and defect planes in the crystal lattice, all of which affect their hardness.

The hardness of diamonds contributes to its suitability as a gemstone. Because it can only be scratched by other diamonds, it maintains its polish extremely well. Unlike many other gems, it is well-suited to daily wear because of its resistance to scratching—perhaps contributing to its popularity as the preferred gem in an engagement ring or wedding ring, which are often worn every day.

Industrial use of diamonds has historically been associated with their hardness; this property makes diamond the ideal material for cutting and grinding tools. As the hardest known naturally-occurring material, diamond can be used to polish, cut, or wear away any material, including other diamonds. However, diamond is a poor choice for machining ferrous alloys at high speeds. At the high temperatures created by high speed machining, carbon is soluble in iron, leading to greatly increased wear on diamond tools as compared to other alternatives. Common industrial adaptations of this ability include diamond-tipped drill bits and saws, or use of diamond powder as an abrasive. Industrial-grade diamonds are either unsuitable for use as gems or synthetically produced, which lowers their value and makes their use economically feasible.

Electrical conductivity

Other specialized applications also exist or are being developed, including use as semiconductors: some blue diamonds are natural semiconductors, in contrast to most other diamonds, which are excellent electrical insulators.[7]

Toughness

Toughness relates to a material's ability to resist breakage from forceful impact. The toughness of natural diamond has been measured as 3.4 MN m-3/2,[9] which is good compared to other gemstones, but poor compared to most engineering materials. As with any material, the macroscopic geometry of a diamond contributes to its resistance to breakage. Diamond is therefore more fragile in some orientations than others.

Color

Diamonds can occur in nearly any color, though yellow and brown are by far the most common.[7] "Black" diamonds are not truly black, but rather contain numerous dark inclusions that give the gems their dark appearance. Colored diamonds contain impurities or structural defects that cause the coloration, while pure or nearly pure diamonds are transparent and colorless. Most diamond impurities replace a carbon atom in the crystal lattice, known as a carbon flaw. The most common impurity, nitrogen, causes a slight to intense yellow coloration depending upon the type and concentration of nitrogen present.[7] The Gemological Institute of America (GIA) classifies low saturation yellow and brown diamonds as diamonds in the normal color range, and applies a grading scale from 'D' (colorless) to 'Z' (light yellow).

A blue diamond recently fetched nearly $8 million. The blue hue was a result of trace amounts of boron in the stone's crystal structure.[10]

Identification

Diamonds can be identified via their high thermal conductivity. Their high refractive index is also indicative, but other materials have similar refractivity. Diamonds do cut glass, but other materials above glass on Mohs scale such as quartz do also. Diamonds easily scratch other diamonds, but this damages both diamonds.

Ruby

Ruby
Ruby is a light pink to blood red gemstone, a variety of the mineral corundum (aluminium oxide). The common red color is caused mainly by the element chromium. Its name comes from ruber, Latin for red. Other varieties of gem-quality corundum are called sapphires. It is considered one of the four precious stones, together with the sapphire, the emerald and the diamond. Improvements used include color alteration, improving transparency by dissolving rutile inclusions, healing of fractures (cracks) or even completely filling them.

Prices of rubies are primarily determined by color (the brightest and best "red" called Pigeon Blood Red, command a huge premium over other rubies of similar quality). After color follows clarity: similar to diamonds, a clear stone will command a premium, but a ruby without any needle-like rutile inclusions will indicate the stone has been treated one way or another. Cut and carat (size) also determine the price.

General
Category Mineral variety
Chemical formula aluminium oxide with chromium, Al2O3::Cr
Identification
Color Red, may be brownish or purplish
Crystal habit Varies with locality. Terminated tabular hexagonal prisms.
Crystal system Trigonal
Cleavage No true cleavage
Fracture Uneven or conchoidal
Mohs Scale hardness 9.0
Luster Vitreous
Refractive index ~1.762-1.770
Pleochroism Orangey Red, Purplish Red
Ultraviolet fluorescence red under longwave
Streak white
Specific gravity 4.0
Melting point 2050°C
Fusibility perfectly
Solubility none
Diaphaneity transparent

Treatments and enhancements

Improving the quality of gemstones by treating them is common yet time-consuming practice. Some treatments are used in almost all cases and are therefore considered "acceptable" practices. The most common treatment is using heat. Most if not all rubies at the lower end of the market are heat treated. Heat treatment is performed on the rough stones to improve color, remove purple tingle, blue patches and silk. These heat treatments typically occur around temperatures of 1800°C (3300°F).[1] Some rubies undergo a process of low tube heat, when the stone is heated over charcoal of a temperature of about 1300°C (2400°F) for 20 to 30 minutes. The silk is only partially broken as the color is improved.

A less acceptable treatment, and one which has gained notoriety in recent years is "Lead Glass Filling" of Rubies. By filling the fractures inside the ruby with so-called lead glass the transparency of the stone is dramatically improved making previously unsuited rubies now fit for applications in jewelry. The process is typically done in 4 steps:
The rough stones are pre-polished to eradicate all surface impurities that may affect the process
The rough is cleaned with hydrogen fluoride
The first heating process whereby no fillers are added. The heating process eradicates impurities inside the fractures. Although this can be done at temperatures up to 1400°C (2500°F) it most likely occurs at a temperature of around 900°C (1600°F) since the rutile silk is still intact
The second heating process in an electrical oven with different chemical additives. Different solutions and mixes have shown to be successful, however mostly lead-containing glass-powder is used at present. The ruby is dipped into oil, then covered with powder, embedded on a tile and placed in the oven where it is heated at around 900°C (1600°F) for one hour in an oxidizing atmosphere. The orange colored powder transforms upon heating into a transparent to yellow-colored paste, which fills all fractures. After cooling the color of the paste is fully transparent, that dramatically improves the overall transparency of the ruby.

In case a color needs to be added, the glass powder can be "enhanced" with copper or other metal oxides as well as elements such as sodium, calcium, potassium etc.

The second heating process can be repeated three to four times consecutively, even applying different mixtures.

Synthetic and imitation rubies

In 1837 Gaudin made the first synthetic rubies by fusing aluminium at a high temperature with a little chromium as a pigment. In 1847 Edelman made white sapphire by fusing alumina in boric acid. In 1877 Frenic and Freil made crystal corundum from which small stones could be cut. Frimy and Auguste Verneuil manufactured artificial ruby by fusing BaF2 and Al2O3 with a little Chromium at red heat. In 1903 Verneuil announced he could produce synthetic rubies on a commercial scale using this flame fusion process.

Other processes in which synthetic rubies can be produced are through the Pulling process, flux process, and the hydrothermal process. Most synthetic rubies originate from flame fusion, due to the low costs involved. Synthetic rubies may have no imperfections visible to the naked eye but magnification may reveal curves striae and gas bubbles. The fewer the number and the less obvious the imperfections, the more valuable the ruby is; unless there are no imperfections (i.e., a "perfect" ruby), in which case it will be suspected of being artificial. Dopants are added to some manufactured rubies so they can be identified as synthetic, but most need gemmological testing to determine their origin.

Imitation rubies have also been present in the gemstone market for some time. Red spinel, red garnet and even glass have been falsely named as rubies. Imitations go back to Roman times and already in the 17th century techniques were developed to color foil red -- by burning scarlet wool in the bottom part of the furnace -- which was then placed under the imitation stone. [4] Trade terms such as balas ruby for red spinel and rubellite for red tourmaline can mislead unsuspecting buyers. Such terms are therefore discouraged from being used by many gemological associations such as the Gemological Institute of America (GIA).

Egypt History

Egypt
Amulet pendant, 254 BCE. Gold, lapis lazuli, turquoise, carnelian, 14 cm wide.

The first signs of established jewellery making in Ancient Egypt was around 3,000-5,000 years ago. The Egyptians preferred the luxury, rarity, and workability of gold over other metals. Predynastic Egypt had already acquired much gold; although the Egyptians acquired gold from the eastern deserts of Africa and from Nubia, in later years they captured it in the spoils of war or acquired it as tributes from other nations.

Jewellery in Egypt soon began to symbolize power and religious power in the community. Although it was worn by wealthy Egyptians in life, it was also worn by them in death, with jewellery commonly placed among grave goods. Unfortunately, grave robbers have destroyed much of the archeological evidence.

In conjunction with gold jewellery, Egyptians used coloured glass in place of precious gems. Although the Egyptians had access to gemstones, they preferred the colours they could create in glass over the natural colours of stones. For nearly each gemstone, there was a glass formulation used by the Egyptians to mimic it. The colour of the jewellery was very important, as different colours meant different things; the Book of the Dead dictated that the necklace of Isis around a mummy’s neck must be red to satisfy Isis’s need for blood, while green jewellery meant new growth for crops and fertility. Although lapis lazuli and silver had to be imported from beyond the country’s borders, most other materials for jewellery were found in or near Egypt, for example in the Red Sea, where the Egyptians mined Cleopatra's favourite gem, the emerald. Egyptian jewellery was predominantly made in large workshops attached to temples or palaces.

Egyptian designs were most common in Phoenician jewellery. Also, ancient Turkish designs found in Persian jewellery suggest that trade between the Middle East and Europe was not uncommon. Women wore elaborate gold and silver pieces that were used in ceremonies.

China History

China

The earliest culture to begin making jewellery in Asia was the Chinese around 5,000 years ago. Chinese jewellery designs were very religion-orientated and contained many Buddhist symbols, a fact which remains to this day.
Jade coiled serpent, Han Dynasty (202 BC-220 AD)

The Chinese used silver in their jewellery more often than gold, and decorated it with their favourite colour, blue. Blue kingfisher feathers were tied onto early Chinese jewellery and later, blue gems and glass were incorporated into designs. However, Chinese preferred jade over any other stone. They fashioned it using diamonds, as indicated in finds from areas in the country. The Chinese revered jade because of the human-like qualities they assigned to it, such as its hardness, durability and beauty. The first jade pieces were very simple, but as time progressed, more complex design evolved. Jade rings from between the 4th and 7th centuries BCE show evidence of having been worked with a compound milling machine; hundreds of years before the first mention of such equipment in the west.

In China, jewellery was worn frequently by both sexes to show their nobility and wealth. However, in later years, it was used to accentuate beauty. Woman wore highly detailed gold and silver head dresses and numerous other items, while men wore decorative hat buttons which showed rank and gold or silver rings. Woman also wore strips of gold on their foreheads, much like women in the Indus Valley. The band served a purpose like an early form of tiara and it was often decorated with precious gems. The most common piece of jewellery worn by Chinese was the earring, which was worn by both men and women. Amulets were also common too, often with a Chinese symbol or dragon. In fact, dragons, Chinese symbols and also phoenixes were frequently depicted on jewellery designs.

The Chinese often placed their jewellery in their graves; most Chinese graves found by archaeologists contain decorative jewellery.

India History

India

The Indian sub-continent has the longest continuous legacy of jewellery making anywhere. While Western traditions were heavily influenced by waxing and waning empires, India enjoyed a continuous development of art forms for some 5000 years.[30] One of the first to start jewellery making were the peoples of the Indus Valley Civilization. By 1,500 BC the peoples of the Indus Valley were creating gold earrings and necklaces, bead necklaces and metallic bangles. Before 2,100 BC, prior to the period when metals were widely used, the largest jewellery trade in the Indus Valley region was the bead trade. Beads in the Indus Valley were made using simple techniques. First, a bead maker would need a rough stone, which would be bought from an eastern stone trader. The stone would then be placed into a hot oven where it would be heated until it turned deep red, a colour highly prized by people of the Indus Valley. The red stone would then be chipped to the right size and a hole drilled through it with primitive drills. The beads were then polished. Some beads were also painted with designs. This art form was often passed down through family; children of bead makers often learnt how to work beads from a young age.

Jewellery in the Indus Valley was worn predominantly by females, who wore numerous clay or shell bracelets on their wrists. They were often shaped like doughnuts and painted black. Over time, clay bangles were discarded for more durable ones. In India today, bangles are made out of metal or glass. Other pieces that women frequently wore were thin bands of gold that would be worn on the forehead, earrings, primitive brooches, chokers and gold rings. The people of the region were much more urbanised than the rest of the area, so the jewellery worn was of heavier make once the civilization developed. Although women wore jewellery the most, some men in the Indus Valley wore beads. Small beads were often crafted to be placed in men and women’s hair. The beads were so small they usually measured in at only one millimetre long.

Unlike many other cultures, Indus Valley jewellery was never buried with the dead. Instead, jewellery was passed down to children or family. Nobility and goldsmiths often hid their jewellery under their floorboards to avoid theft.

As time progressed, the methods for jewellery advanced, thus allowing complex jewellery to be made. Necklaces were soon adorned with gems and green stone.

Although they used other gems prior, India was the first country to mine diamonds, with some mines dating back to 296 BC. However, axes dating to 4,000 BC found in China from previous factions of the country, contain traces of diamond dust used to sharpen the blades. While China used the diamonds they found mainly for carving jade, India traded the diamonds, realising their valuable qualities. This trade almost vanished 1,000 years after Christianity grew as a religion, as Christians rejected the diamonds which were used in Indian religious amulets. Along with Arabians from the Middle East restricting the trade, India’s diamond jewellery trade lulled.

Today, many of the jewellery designs and traditions are still used and jewellery is commonplace in Indian ceremonies and weddings.

Pacific History

Pacific
Main article: Jewellery in the Pacific

Jewellery making in the Pacific started later than in other areas because of relatively recent human settlement. Early Pacific jewellery was made of bone, wood and other natural materials, and thus, has not survived. Most Pacific jewellery is worn above the waist, with headdresses, necklaces, hair pins and arm and waist belts being the most common pieces amongst island cultures. Jewellery made of flowers in Hawaii are called leis and are now commonly associated with that area and its relaxed, tourist friendly attitude.

Jewellery in the Pacific, with the exception of Australia, is worn to be a symbol of either fertility or power. Elaborate headdresses are worn by many Pacific cultures and some, such as the inhabitants of Papua New Guinea, wear certain headresses once they have killed an enemy. Like the typical tribal cliché, many tribesman wear boar bones through their noses.

Island jewellery is still very much primal because of the lack of communication with outside cultures; some areas of Borneo and Papua New Guinea are yet to be explored by Western nations. However, the island nations which were flooded with Western missionaries have had drastic changes made to their jewellery designs. Missionaries saw any type of tribal jewellery as a sign of the wearer's devotion to paganism. Thus many tribal designs were lost forever in the mass conversion to Christianity.
A modern opal bracelet from Australia.

Australia is now the number one supplier of opals in the world. Although Australia wasn’t colonised until later on in history, it is now famous for its vast supplies of opals. Opals had already been mined in Europe and South America for many years prior, but in the late 1800’s, the Australian opal market entered as the dominant producer of opals. Australian opals are only mined in a few select places around the country, making it one the most profitable stones in the Pacific.

One of the few cultures to today still create their jewellery as they did many centuries prior is the New Zealand Māori, who create Hei-tiki. The reason the hei-tiki is worn is not apparent; it may either relate to ancestral connections, as Tiki was the first Māori, or fertility, as there is a strong connection between this and Tiki. Another suggestion from historians is that the Tiki is a product of the ancient belief of a god named Tiki, perhaps dating back to before the Māoris settled in New Zealand. Hei-tikis are traditionally carved by hand from bone (commonly whale), nephrite or bowenite; a lengthy and spiritual process. The Hei-tiki is now popular amongst tourists who can buy it from souvenir or jeweller shops.

Other than jewellery created through Māori influence, jewellery in New Zealand remains similar to other western civilizations; multi cultural and varied. This is more noticeable in New Zealand because of its high levels of non-European citizens.

Americas History

Americas

Jewellery played a major role in the fate of the Americas when the Spanish established an empire to seize South American gold. Jewellery making developed in the Americas 5,000 years ago in Central and South America. Large amounts of gold was easily accessible, and the Aztecs and Mayans created numerous works in the metal. Among the Aztecs, only nobility wore gold jewellery, as it showed their rank, power and wealth. Gold jewellery was most common in the Aztec Empire and was often decorated with feathers from birds. The main purpose of Aztec jewellery was to draw attention, with richer and more powerful Aztecs wearing brighter, more expensive jewellery and clothes. Although gold was the most common and popular material used in Aztec jewellery, silver was also readily available throughout the American empires. In addition to adornment and status, the Aztecs also used jewellery in sacrifices to appease th gods. Priests also used gem encrusted daggers to perform animal and human sacrifices.

Another ancient American civilization with expertise in jewellery making was the Maya. At the peak of their civilization, the Maya were making beautiful jewellery from jade, gold, silver, bronze and copper. Maya designs were similar to those of the Aztecs, with lavish head dresses and jewellery. The Maya also traded in precious gems. However, in earlier times, the Maya had little access to metal, so made the majority of their jewellery out of bone or stone. Merchants and nobility were the only few that wore expensive jewellery in the Maya Empire, much the same as with the Aztecs.

In North America, Native Americans used shells, wood, turquoise, and soapstone, almost unavailable in South and Central America. The Native Americans utilized the properties of the stone and used it often in their jewellery, particularly in earlier periods. The turquoise was used in necklaces and to be placed in earrings. Native Americans with access to oyster shells, often located in only one location in America, traded the shells with other tribes, showing the great importance of the body adornment trade in Northern America.

Although initially of interest either as a curiosity or a source of raw material, jewellery designs from the Americas has come to play a significant role in modern jewellery

Greece History

Greece
Gold earring from Mycenae, 16th century BCE.

The Greeks started using gold and gems in jewellery in 1,400 BC, although beads shaped as shells and animals were produced widely in earlier times. By 300 BC, the Greeks had mastered making coloured jewellery and using amethysts, pearl and emeralds. Also, the first signs of cameos appeared, with the Greeks creating them from Indian Sardonyx, a striped brown pink and cream agate stone. Greek jewellery was often simpler than in other cultures, with simple designs and workmanship. However, as time progressed the designs grew in complexity different materials were soon utilized.
Pendant with naked woman. Electrum, Rhodes, ca. 630-620 BCE.

Jewellery in Greece was hardly worn and was mostly used for public appearances or on special occasions. It was frequently given as a gift and was predominantly worn by woman to show their wealth, social status and beauty. The jewellery was often supposed to give the wearer protection from the “Evil Eye” or endowed the owner with supernatural powers, while others had a religious symbolism. Older pieces of jewellery that have been found were dedicated to the Gods. The largest production of jewellery in these times came from Northern Greece and Macedon. However, although much of the jewellery in Greece was made of gold and silver with ivory and gems, bronze and clay copies were made also.
Ancient Greek jewellery from 300 BCE.

Jewellery makers in Ancient Greece were largely anonymous. They worked the types of jewellery into two different styles of pieces; cast pieces and pieces hammered out of sheet metal. Fewer pieces of cast jewellery have been recovered; it was made by casting the metal onto two stone or clay moulds. Then the two halves were joined together and wax and then molten metal, was placed in the centre. This technique had been in practised since the late Bronze Age. The more common form of jewellery was the hammered sheet type. Sheets of metal would be hammered to the right thickness & then soldered together. The inside of the two sheets would be filled with wax or another liquid to preserve the metal work. Different techniques, such as using a stamp or engraving, were then used to create motifs on the jewellery. Jewels may then be added to hollows or glass poured into special cavities on the surface.

The Greeks took much of their designs from outer origins, such as Asia when Alexander the Great conquered part of it. In earlier designs, other European influences can also be detected. When Roman rule came to Greece, no change in jewellery designs was detected. However, by 27 BC, Greek designs were heavily influenced by the Roman culture. That is not to say that indigenous design did not thrive; numerous polychrome butterfly pendants on silver foxtail chains, dating from the 1st century, have been found near Olbia, with only one example ever found anywhere else.

Middle Ages History

Middle Ages
Merovingian fibulae, Bibliothèque Nationale de France.
Eagle-shaped Visigothic cloisonné fibula from Guadalajara, Spain. Bronze. 6th century.

Post-Roman Europe continued to develop jewellery making skills; the Celts and Merovingians in particular are noted for their jewellery, which in terms of quality matched or exceeded that of Byzantium. Clothing fasteners, amulets, and to a lesser extent signet rings are the most common artefacts known to us; a particularly striking celtic example is the Tara Brooch. The Torc was common throughout Europe as a symbol of status and power. By the 8th century, jewelled weaponry was common for men, while other jewellery (with the exception of signet rings) seems to become the domain of women. Grave goods found in a 6th-7th century burial near Chalon-sur-Saône are illustrative; the young girl was buried with: 2 silver fibulae, a necklace (with coins), bracelet, gold earings, a pair of hair-pins, comb, and buckle. The Celts specialized in continuous patterns and designs; while Merovignian designs are best known for stylized animal figures. They were not the only groups known for high quality work; note the Visigoth work shown here, and the numerous decorative objects found at the Anglo-Saxon Ship burial at Sutton Hoo Suffolk, England, are a particularly well-known example. On the continent, cloisonné and garnet were perhaps the quintessential method and gemstone of the period.
Byzantine wedding ring.

The Eastern successor of the Roman Empire, the Byzantine Empire, continued many of the methods of the Romans, though religious themes came to predominate. Unlike the Romans, the Franks, and the Celts, however; Byzantium used light-weight gold leaf rather than solid gold, and more emphasis was placed on stones and gems. As in the West, Byzantine jewellery was worn by wealthier females, with male jewellery apparently restricted to signet rings. Like other contemporary cultures, jewellery was commonly buried with its owner

Rome History

Rome
Roman Amethyst intaglio pendant, c. 212 CE; later converted to St. Peter medallion.
Although jewellery work was abundantly diverse in earlier times, especially among the barbarian tribes such as the Celts, when the Romans conquered most of Europe, jewellery was changed as smaller factions developed the Roman designs. The most common artefact of early Rome was the brooch, which was used to secure clothing together. The Romans used a diverse range of materials for their jewellery from their extensive resources across the continent. Although they used gold, they sometimes used bronze or bone and in earlier times, glass beads & pearl. As early as 2,000 years ago, they imported Sri Lankan sapphires and Indian diamonds and used emeralds and amber in their jewellery. In Roman-ruled England, fossilized wood called jet from Northern England was often carved into pieces of jewellery. The early Italians worked in crude gold and created clasps, necklaces, earrings and bracelets. They also produced larger pendants which could be filled with perfume.

Like the Greeks, often the purpose of Roman jewellery was to ward off the “Evil Eye” given by other people. Although woman wore a vast array of jewellery, men often only wore a finger ring. Although they were expected to wear at least one ring, some Roman men wore a ring on every finger, while others wore none. Roman men and women wore rings with a carved stone on it that was used with wax to seal documents, an act that continued into medieval times when kings and noblemen used the same method. After the fall of the Roman Empire, the jewellery designs were absorbed by neighbouring countries and tribes.

Europe and the Middle East History

History
The first signs of jewellery came from the Cro-Magnons, ancestors of Homo sapiens, around 40,000 years ago. The Cro-Magnons originally migrated from the Middle East to settle in Europe and replace the Neanderthals as the dominant species. The jewellery pieces they made were crude necklaces and bracelets of bone, teeth and stone hung on pieces of string or animal sinew, or pieces of carved bone used to secure clothing together. In some cases, jewellery had shell or mother-of-pearl pieces. In southern Russia, carved bracelets made of mammoth tusk have been found. Most commonly, these have been found as grave-goods. Around 7,000 years ago, the first sign of copper jewellery was seen.

Europe and the Middle East
By approximately 4,000 years ago, jewellery-making had become a significant craft in the cities of Sumer and Akkad. The most significant archaeological evidence comes from the Royal Cemetery of Ur, where hundreds of burials dating 2900–2300 BC were unearthed; tombs such as that of Puabi contained a multitude of artefacts in gold, silver, and semi-precious stones, such as lapis lazuli crowns embellished with gold figurines, close-fitting collar necklaces, and jewel-headed pins. In Assyria, men and women both wore extensive amounts of jewellery, including amulets, ankle bracelets, heavy multi-strand necklaces, and cylinder seals.

Jewellery in Mesopotamia tended to be manufactured from thin metal leaf and was set with large numbers of brightly-coloured stones (chiefly agate, lapis, carnelian, and jasper). Favoured shapes included leaves, spirals, cones, and bunches of grapes. Jewellers created works both for human use and for adorning statues and idols; they employed a wide variety of sophisticated metalworking techniques, such as cloisonne, engraving, fine granulation, and filigree.

Extensive and meticulously maintained records pertaining to the trade and manufacture of jewellery have also been unearthed throughout Mesopotamian archaeological sites. One record in the Mari royal archives, for example, gives the composition of various items of jewellery:“ 1 necklace of flat speckled chalcedony beads including: 34 flat speckled chalcedony bead, and 35 gold fluted beads, in groups of five.

1 necklace of flat speckled chalcedony beads including: 39 flat speckled chalcedony beads, with 41 fluted beads in a group that make up the hanging device.

1 necklace with rounded lapis lazuli beads including: 28 rounded lapis lazuli beads, and 29 fluted beads for its clasp.