It has a refractive index of 1 655 to 1 684. Approximately the same as that of spodumene its specific gravity is 3 23 to 3 27 placing it between apatite and diopside on the density scale. This can be seen more often in faceted gemstones than in cabochon sillimanite gems. It is a very difficult stone to cut. Sillimanite gems may show a cat s eye and be cut en cabochon or they may be faceted transparent gemstones.
A fibrous variety of sillimanite is traded as fibrolite. In the past these gemstones were mined in places such as sri lanka kenya burma and usa. Beautiful sillimanite cabochons for sale online. Some sillimanite gemstones show pleochroism which means that several colors may be exhibited in a single gemstone depending on the viewing angle. Gem quality sillimanite is usually translucent and is very rarely found in transparent form.
Compact masses of sillimanite were once used by native americans of the american southwest as fashion tools. Sillimanite is a brittle stone rating a 6 7 on the hardness scale. Sillimanite cat s eye cabochon natural brown cat s eye oval shape matched pair cabochon gemstone cat s eye smooth loose gemstone 8x7x5 mm qualityrealgems 5 out of 5 stars 2 9 00 18 00 18 00 50 off. Historically sillimanite is a rare gemstone known mainly to collectors. Sillimanite is considered to stimulate the production of endorphins in the human body.
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Sillimanite cats eye colors. 63 15 carats 22 71 x 22 40 x 13 93 mm. Buy now and receive 10 off your first purchase. The cats eye that runs down the stone is a silver stripe. It is even believed increasing energy and a general feeling of well being.Like diamond topaz and fluorite sillimanite has perfect cleavage. Sillimanite has a hardness of 6 5 to 7 5 on the mohs scale and a vitreous to silky luster. Sillimanite occurs in a number of colors. The colors of sillimanite include colorless grayish white green bluish and brownish. Therefore only skilled lapidaries should attempt to do so.
When polished as cabochons they glow mysteriously like a cats eye at night. Sillimanite clarity and luster. Cat s eye sillimanite is almost always brownish in color but high quality gemstones can exhibit a very strong violet hue. Gem news 2011 v2 pala international sillimanite aka fibrolite was named after benjamin silliman a professor of chemistry and geology at yale university in 1824. The main body tone of the stone is uaully reddish black but can be found in various colours like yellow black pale blue and glow red.
The main body tone of the stone is uaully reddish black but can be found in various colours like yellow black pale blue and glow red. When polished as cabochons they glow mysteriously like a cats eye at night. Like diamond topaz and fluorite sillimanite has perfect cleavage. Sillimanite cats eye colors. Compact masses of sillimanite were once used by native americans of the american southwest as fashion tools.
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Gem news 2011 v2 pala international sillimanite aka fibrolite was named after benjamin silliman a professor of chemistry and geology at yale university in 1824. A fibrous variety of sillimanite is traded as fibrolite. It has a refractive index of 1 655 to 1 684.
