Natural Gemstones: Reference Facts
Green Tourmaline
Tourmaline is a gemstone that occurs in almost every color; however, the widely known variety is Green Tourmaline. Green tourmaline comes in a wide range of shades from light yellow-green to dark green. The yellow-green is the most common, but the emerald-green is much rarer and more valuable. Tourmaline is the most dichroic of all gemstones, so green tourmaline with a pure green color is extremely rare. Fine green tourmaline with emerald-green color is the most desirable. Its color is very beautiful and similar to the color of fine emerald, which is in one of the most expensive gemstones.
Green tourmaline is one of the most popular gemstones. It is very durable and has excellent wearing quality. This is the ideal gemstone to work into jewelry.
Since ancient days, Green tourmaline is believed to strengthen the body and spirit. This gemstone is a symbol of love and friendship. It is the modern birthstone for October and is the suggested gift for the 8th anniversary.
| Green Tourmaline Known Facts
|
| Color |
Green, Yellowish Green, Yellow-Green
|
| Clarity
|
Type I – usually eye clean and very high clarity under magnification
|
| Crystal Structure
|
Trigonal
|
| Chemical Composition
|
Na(Li,Al)3Al6(BO3)3Si6O18(OH)4 - Complex borosilicate
|
| Luster
|
Vitreous
|
| Optic Character
|
Doubly Refractive
|
| Durability
|
Very Good
|
| Specific Gravity(SG)
|
3.06
|
| Refractive Index(RI)
|
1.62-1.64
|
| Birefringence
|
0.018
|
| Hardness
|
7.5
|
| Occurrence
|
Brazil, Afghanistan, Pakistan, Mozambique, Madagascar, Nigeria, the United States
|
|
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