Princely Green Gem- Tsavorite
“Tsavorite" ，also named “tsavolite” "green grossularite”，belongs to garnet family, common saying”follow me”(pronunciation in Chinese), but it is different from ordinary dark-red garnet. Tsavorite and demantoid are the similar bright-colored green gem, beautiful characteristic and rare output. The two kinds of green gem are like emerald in appearance, especially tsavorite, which was often on sale as emerald , but we can distinguish them by polariscope. Besides, demantoid is more like green diamond because of its high dispersion value 0.057 (more than diamond's dispersion value 0.044 ) .
Tanzania found a series of tsavorite resource in the 1960s, due to neighboring country’s successful inspiration, Kenya is willing to prospect the mineral area nearby southern Tanzanian. Kenya discovered tsvorite resource in 1970,and started commercial mine soon afterwards.In 1973 Kenya had already mined over 1 kilogram crystals to launch on the market, The name of “tsavorite” was defined in 1974, because of its source in Tsavo National Park,where was almost the only producing area. A private perfectly 16.7 carat crystal may be the world biggest high-quality tsavorite.
Tsavorite produced in the region of Kenya National Park, far away from 350 kilometers of eastern Nairobi(capital of Kenya),besides,Tanzania also produced tsavorite era.
Physical and chemical characteristics of tsavorite
1. English name: tsavorite
2. Ingredient:calcium aluminum silicate
3. Mohs’: hardness: 7 - 8
4. S.G.: 3.57-3.65
5. Refractive index: 1.73-1.75
6. Double refractive index: none
7. Optical character: isotropic body, often anomalous extinction
8. Magnification: short columnar or round crystal inclusion , heatwave effect
9. Affixation explanation: There are two kinds of variations: one kind is a lucency crystal; the other kind is a lump crystal. Tsavorite which produced in South Africa also named “Transvaal jade”, often included dark magnetite fleckers.
Producing area and valuation of tsavorite
Producing area: Canada, Sri Lanka, Pakistan, The former Soviet Union, Tanzania, South Africa , and USA.
Valuation of garnet based on its color, clarity and grain size, for example,the highest value of garnet are demantoid and tsavorite. In green gem,although tsavorite launched on market lately than emerald which had been the most favorable green gem for a long time , but its hardness and value are almost the same as emerald, even more. According to scientist’s measure, tsavorite has 200 times hardness than emerald, and the brightness is 2 times. Especially, tsavorite often has good clarity , luster, and little inclusion, so as to saving many process .Such a nice quality keep very high fascination to most jewellers.
( 站長註解:本譯文與雜誌的譯文略有不同，乃因譯者不同之故 )