74 NEW YORK STATE MUSEUM 



closely resembles magnetite and is chiefly distinguished by its 

 slight tendency to attract the magnet and by its characteristic 

 association with zincite and willemite at Franklin and Ogdens- 

 burg X. J. its most notable localities. 



It is used at Franklin with other ores for the production of 

 zinc and of an alloy of iron and manganese known as 

 spiegeleisen. 



Chromite (chromic iron) FeO.Ci\,0 3 



Chroinite, the iron chromate, contains GS r ; chromium sesqui- 

 oxid and 32$ iron protoxid. 



Chromite is rarely found in small octahedral crystals. It 

 commonly occurs as a black massive mineral resembling massive 

 magnetite, sometimes in disseminated grains and sand. It is, 

 in some instances, feebly magnetic. 



It occurs in veins or embedded masses in serpentine and may 

 often be recognized by its association with that mineral. 



Turkey and Xew Caledonia furnish much of the chromite now 

 used. A somewhat lower grade ore is found in extensive 

 deposits in California. 



Chromium extracted from chromite is used in the production 

 of several pigments, in the manufacture of bichromate of potash 

 for calico printing and for chrome steel. 



Chrysoberyl BeO.ALCL 



Chrysoberyl is the aluminate of beryllium and contains S0.2<£ 

 alumina and 10. S r < glucina. 



The crystals of chrysoberyl. which are orthorhombic, are com- 

 monly twinned producing pseudohexagonal shapes which some- 

 times show reentrant angles. The crystals are generally tabular 

 in habit with intersecting, featherlike striation due to repeated 

 twinning. Chrysoberyl is transparent to translucent, of a vit- 

 reous luster and of various colors from a pale yellowish green 

 to emerald-green. The variety alexandrite is of an emerald-green 

 color by reflected light which, however, changes to a columbine- 

 red by transmitted light. 



Brazil, Ceylon, Moravia and the Ural mountains of Eussia pro- 

 duce chrysoberyl. It has been found at Haddam Ct. and at 

 Greenfield X. Y. 



Chrysoberyl is used as a gem, the varieties alexandrite and 

 cat's eye being specially prized. 



