CATALOGUE OF GEMS AND PRECIOUS STONES. 187 



G. 



Gadolinite=velvety-black yttrium, beryllium, iron silicate, and silicates of other 

 elements. 



Gahnite=green zinc spinel. 



Garnet=group of silicate minerals. The species are: Almandite, aluminum and iron 

 silicate; andradite, iron and calcium silicate; grossularite, aluminum and calcium 

 silicate; pyrope, aluminum and magnesium silicate; spessartite, aluminum and man- 

 ganese silicate; uvarovite, chromium and calcium silicate. 



Garnierite=green nickel and magnesium hydrous silicate. 



Gem = cut and polished precious stone. 



G emstone =gem . 



Geneva ruby=synthetic ruby made in Geneva, Switzerland. 



Geyserite= siliceous deposit from a geyser. 



Gibraltar stone=banded, mottled, or clouded calcium carbonate. 



Girasol=corundum cat's-eye with a bluish, reddish, or yellowish reflection of light, 

 lighter in shade than the stone itself, which moves on the surface of the stone like 

 the lines of a starstone; also opal (see girasol opal); also moonstone (feldspar). 



Girasol opal = fire opal. 



Glass= artificial noncrystallized substance composed of silica and several bases, 

 notably an alkali and lead. 



Glass agate = obsidian. 



Goethite=iron hydrous oxide. 



Golconda diamond = diamond obtained from the regions watered by Krishna and 

 Godavari Rivers but polished in Golconda, India. 



Gold=metallic element, often mounted as found, as a nugget. 



Gold opal = opal which shows yellowish light over a large area. 



Gold quartz = massive quartz inclosing gold. 



Golden beryl=clear bright-yellow beryl. 



Golden stone = greenish -yellow chrysolite (olivine). 



Golden topaz=topaz of a golden-yellow color; also golden-yellow citrine (quartz). 



Goldstone=aventurine. An imitation of goldstone consists of glass with included metal 

 filings (fraudulently sold as fire agate). 



Gooseberry stone = brownish -green grossularite (garnet). 



Goshenite= colorless, white, or bluish beryl from Goshen, Massachusetts. 



Goutte d'eau=colorless topaz. 



Goutte de sang=blood-red spinel. 



Graphic granite = pegmatite composed of quartz and feldspar so arranged as to simu- 

 late writing. 



Green agate=zonochlorite. 



Green garnet=any green garnet; also incorrectly applied to green enstatite from 

 South Africa. 



Green starstone=chlorastrolite. 



Greenstone =zonochlorite; also chlorastrolite ; also californite (vesuvianite). 



Grossularite=pale-green or yellow garnet. 



Guarnaccino=yellowish-red garnet. Same as vermeille. 



Gypsum = calcium hvdroUs sulphate. 



H. 



Hair stone=quartz with inclusions of hairlike crystals or fibers of some other mineral. 



Same as sagenite. 

 Harlequin opal=opal in which the colors form a minute mosaic or are set in small 



squares. 

 Hatchet stone=nephrite. 



