CATALOGUE OF GEMS AND PRECIOUS STONES. 197 



Star stone =starolite (quartz). 



Star ruby=ruby (corundum) showing a star of light. 



Star sapphire = grayish-blue sapphire (corundum) showing a star of light. 



Star topaz = aster iated oriental topaz (yellow corundum). 



Starolite= aster iated quartz. 



Staurolite=aluminum, iron, and magnesium hydrous silicate. 



Steinheilite = cordier ite . 



Stibiotantalite=antimony tantalate. 



Succinite = amber; also amber-colored grossularite (garnet). 



Sulphur diamond=pyrite. 



Sun opal=fire opal. 



Sunstone=feldspar (xisually oligoclase or labradorite) containing inclusions of minute 



scales of iron oxide. 

 Swiss lapis=agate or jasper artificially colored blue. 

 Synthetic gem=one artificially made from chemicals. 

 Syrian garnet=almandite (garnet) of a violet shade. 



Tabasheer=amorphous opal-like silica deposited in the joints of bamboo. 



Tauridan topaz = very pale blue topaz. 



Taxoite= serpentine from Chester County, Pennsylvania. 



Test stone =basanite (jasper). 



Texas agate = agate jasper from Texas. 



Thetis hairstone= transparent quartz with inclusions of hairlike crystals of green 

 actinolite. 



Thomsonite=zeolite, aluminum, calcium, and sodium hydrous silicate. 



Thulite=rose-red zoisite. 



Tiger-eye = yellow to brown, altered crocidolite. 



Titanite=calcium and titanium silicate. 



Toad's-eye tin=concentric cassiterite. Same as wood tin but on a smaller scale. 



Topaz=aluminum silicate, with fluorine. Most of the ordinary topaz of commerce 

 is ' ' false topaz " or yellow to brown quartz. Much of the ' ' yellow quartz " is smoky 

 quartz artificially changed from brown to yellow by heat. The term topaz is also 

 improperly applied to any yellow stone. 



Topaz cat's-eye=yellow corundum showing an elongated or round patch of opalescent 

 light. 



Topazolite= colorless, yellowish, or greenish andradite (garnet). 



Touchstone =basanite (jasper). 



Tourmaline =group of closely related minerals which are complex hydroboro-silicates 

 of aluminum and one or more other bases, such as iron, manganese, calcium, mag- 

 nesium, sodium, or lithium. 



Trainite= impure banded variscite. 



Tree agate = mocha stone. 



Tree stone=mocha agate. 



Trenton diamond=quartz crystal from Herkimer County, New York. 



Trilobite= fossil. 



Triphane= yellow or greenish-yellow spodumene. 



Troostite=pink to gray willemite containing some manganese. 



Turquoise =aluminum and copper hydrous phosphate. 



Turkis= turquoise. 



Turtle back=chlorastrolite; also matrix turquoise; also matrix variscite. 



U. 



Unripe diamond = quartz. 

 Ural chrysoberyl=alexandrite. 



