 | |  | Tourmaline is the most colorful of all gemstones. It occurs in all colors, but pinkish, red, dark-green, bluish and multicolored are its nearly well-known jewel colors. Scientifically, tourmaline is not a single mineral, but a group of minerals related in their physical and chemic backdrop. The mineral Elbaite is the member of the Tourmaline group that is responsible for almost all the precious stone varieties. 3 other members of the group - Schorl, Dravite and Liddicoatite, are seldom used as gemstones.
| | | Chemic Formula | Tourmaline is a serial of several unlike minerals with unique chemic formulas. See The chemical formula of Tourmaline for details. | | Colour | White, Colorless, Blueish, Red, Green, Yellow, Orange, Brownish, Pink, Majestic, Gray, Black, Multicolored | | Hardness | 7 - 7.5 | | Crystal Organisation | Hexagonal | | Refractive Alphabetize | 1.616 - 1.650 | | SG | ii.9 - iii.3 | | Transparency | Transparent to opaque | | Double Refraction | .018 | | Luster | Vitreous | | Cleavage | 3,2 | | Mineral Class | Tourmaline | |
| Though Elbaite occurs in all color forms, the term Elbaite in the gemstone merchandise is sometimes used to describe the green class of Tourmaline. The other color forms of Elbaite have their ain variety names on the gem market. Traditional Tourmaline gemstone variety names include Rubellite, the red or pinkish variety, Indicolite, the blue diverseness, and Watermelon Tourmaline, a multicolored Tourmaline of green and scarlet. More recently coined Tourmaline variety names include Chrome Tourmaline and Paraiba Tourmaline. A contempo trend in the gem market place is to prefix Tourmaline gemstones by the color designation as opposed to diversity name, such that "Rubellite" is at present more often called "Red Tourmaline". The value of Tourmaline has a very large range. The more than common forms tin be adequately cheap, only the rarer and more exotic colors can command very high prices. The most expensive and valuable form of Tourmaline is the rare neon-blue form known by the trade name Paraiba Tourmaline. Paraiba Tourmaline was start discovered in a gem pegmatite in the Brazilian country of Paraiba in 1989. This new Tourmaline became extremely popular in a very short time, and the cost for this rare Tourmaline became astronomically high due to short supply. Small deposits of Tourmaline of similar color to Paraiba Tourmaline were too recently institute in Nigeria and Mozambique, and these are often also called "Paraiba Tourmaline" in the jewel trade. Other valuable forms of Tourmaline are Chrome Tourmaline, an intense-dark-green Tourmaline found in Tanzania, Rubellite, the pinkish to reddish variety, and Indicolite, the rare blue diversity. Multicolored stones are truly a gemological wonder, as their beauty and uniqueness are unparalleled. An interesting form of multicolored tourmaline, adequately chosen Watermelon Tourmaline, has a cerise eye surrounded by a green outer layer (or vice versa). When used every bit a precious stone, Watermelon Tourmaline is green on one side and red on the other. Schorl, a common black Tourmaline, is fairly cheap. All colored Tourmaline gems display pleochroism, meaning their colour changes when viewed at different angles. In some Tourmaline gems, this effect is hardly noticeable, while in others it is strongly apparent. Gemstone cutters must accept this into account when cut a Tourmaline, then that the finished gem brings out its all-time color. As mentioned to a higher place, virtually all Tourmaline gemstones are of the Elbaite type. Schorl, Dravite, and Liddicoatite are occasionally used equally gemstones. Schorl, known as "Black Tourmaline" makes a dark, opaque, yet shiny black gemstone. Dravite is almost e'er brownish in colour, and usually opaque. However, transparent forms do occasionally occur, and these can be used as rare dark-brown gemstones. Night brown Dravite may exist heat-treated to lighten its dark color. Liddicoatite occurs in a smashing variety of colors and in excellent multicolored forms, but is too rare to be used extensively every bit a gemstone. |
| Tourmaline of all colors are faceted into gems for jewelry, merely the red, green, blue, and multicolored stones, peculiarly watermelon, are the virtually popular. Tourmaline tin exist institute in fairly large transparent crystals, and these tin can produce very large exquisite and flawless gemstones. Tourmaline is used as a big pendant rock, in bracelets, rings, and earrings. Lesser quality stones are cut into cabochons, and are also polished into beads and used in bracelets and necklaces. Pink and light-green Tourmalines from certain localities comprise tiny, parallel inclusions, causing them to display a stiff cat's eye effect when polished. Such stones are oftentimes cut equally cabochons and chosen "Cats' Center Tourmaline" . Some pink, green, and multicolored Tourmalines are also carved into ornamental figures and carvings. |
- Achroite - Colorless variety of Tourmaline.
- Canary Tourmaline -Bright xanthous Tourmaline from a recent deposit in Malawi.
- Cat'southward Center Tourmaline - Tourmaline displaying a cat's eye outcome.
- Chrome Tourmaline -Tourmaline with a deep greenish colour caused by chromium impuritiess.
- Dravite - Brown multifariousness of Tourmaline. See the mineral Dravite for additional information.
- Elbaite -Individual member mineral of the Tourmaline group, and the Tourmaline course responsible for almost all Tourmaline gemstones. In the gem industry, the term Elbaite often connotes the greenish form, and occasionally the multicolored grade. Encounter the mineral Elbaite for additional information.
- Indicolite - Light to night blueish variety of Tourmaline.
- Paraiba Tourmaline -Neon blueish, highly desirable diversity of Tourmaline that originated in Paraiba, Brazil. Its interesting color is caused by inclusions of copper. Although technically the term describes only those Tourmalines from Paraiba in Brazil, the gem trade now uses it to describe whatever light to neon blue Tourmaline from any worldwide location.
- Rubellite - Pink to red variety of Tourmaline.
- Schorl -Black form of Tourmaline. See the mineral Schorl for boosted data.
- Siberite - Occasionally used to depict purple Tourmaline.
- Verdelite -Occasionally used to describe green Tourmaline.
- Watermelon Tourmaline - Multicolored Tourmaline with a scarlet center, surrounded by a light-green outer layer (or vice versa). Watermelon gemstones are multicolored red and green.
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| Rut treatment tin can heighten the color of some Tourmalines. Some green stones can be made deep greenish, some brownish-red stones can be made carmine, and some light pink stones can be made colorless through heating. The color of some light colored stones can likewise exist fabricated into a deeper hue, and dark, transparent Dravite can exist made lighter. |
Important deposits of Tourmaline are in Afghanistan, Pakistan, Russia, Burma (Myanmar), Sri Lanka (Ceylon), and the United states (California and Maine). Several African countries accept recently become big producers of gem Tourmaline, specifically Madagascar, Namibia, Mozambique, Tanzania, Nigeria, and Republic of malaŵi.
| Considering of all the different colors of Tourmaline, information technology tin can be confused with numerous gemstones. The most prevalent Tourmaline gemstone colors and those they can exist confused with are listed below:
Green Tourmaline - Emerald, Peridot, Demantoid, and Tsavorite.
Ruby-red Tourmaline - Ruby, Spinel, Garnet.
Pink Tourmaline - Kunzite, Spinel, Pinkish Topaz, Morganite, Pink Sapphire.
Blue Tourmaline - Aquamarine, Blue Topaz, Sapphire, Zircon.
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