KYANITE. 



173 



The analyses of bucholzite and sillimanite give varying results, and 

 still they make but one species. Fibrolite is another variety of thia 

 mineral from the Carnatic. 



KYANITE. 



Triclinic. Usually in long thin-bladed crystals aggre- 

 gated together, or penetrating the gangue. The annexed 

 figure is a portion of one of these crystals. Crystals ^^\ 

 sometimes short and stout. Lateral cleavage, dis- 

 tinct. Sometimes fine fibrous. 



Color usually light blue, sometimes white, or a 

 blue center, with a white margin ; sometimes gray, 

 green, or even black. Luster of flat face a little 

 pearly. H=5— 7. Rather brittle, but less so than 

 Sillimanite. Gr=3'6— 3.7. 



Composition: silica 37*0, alumina 63*0. Unaltered alone 

 before the blowpipe. With borax forms slowly a transparent 

 colorless glass. 



Dif. Distinguished by its infusibility from varieties of 

 the hornblende family. The short crystals have some re- 

 semblance to staurotide, but their sides and terminations are 

 usually irregular ; they differ also in their cleavage and 

 luster. 



Obs. Found in gneiss and mica slate, and often accom-. 

 panied by garnet and staurotide. 



Occurs in long-bladed crystallizations at Chesterfield and 

 Worthington, Mass. ; at Litchfield and Washington, Conn. ; 

 near Philadelphia ; near Wilmington, Delaware ; and in 

 Buckingham and Spotsylvania counties, Va. Short crystals 

 (sometimes called improperly fibrolite) occur in gneiss at 

 Bellows Falls, Vt., and at Westfield and Lancaster, Mass. 



In Europe, transparent crystals are met with at St. Goth- 

 ard in Switzerland, and in Styria, Carinthia, and Bohemia 

 Villa Rica in South America, affords fine specimens. 



The name kyanite is from the Greek kuanos, sky-blae. 

 It is also called sappar, a corruption of sapphire ; also dis- 

 thene, and when white, rhcetizite. 



Uses. Kyanite is sometimes used as a gem, and has 

 some resemblance to sapphire. 



Warlhite Resembles kyanite, but gives off water before the blow- 

 pipe. It may be an altered kyanite. From St. Petersburg. 



Describe kyanite 1 What is "he origin of the name ? For what is 

 it used I 



15* 



