SUBSTLICATES. 



291 



and pyroxene, at Gouverneur, near Natural Bridge in Lewis 

 County (the variety called Lederite); in Orange County in 

 Monroe, Edenville, Warwick, and Amity ; near Peekskill in 

 Westchester County, and near West Farms ; in Massachu- 

 setts, at Lee, Bolton, and Pelham ; in Connecticut, at Trum- 

 bull ; in Maine, at Sanford, and Thomaston ; in New Jer- 

 sey, at Franklin ; in Pennsylvania, near Attleboro', Bucks 

 County ; in Delaware, at Dixon's quarry, 7 miles from 

 Wilmington ; in Maryland, 25 miles from Baltimore, on 

 the Gunpowder. 



Guarinite. Like sphene in composition, but trimetric. 



Keilhauite, or Yttro-titanite. Related to sphene. Brownish-black, 

 with a grayish-brown powder. G. =3*69. H. =6'5. Fuses easily. 

 Affords Silica 30 0, titanic acid 29 0, yttria 9*6, lime 18*9, iron sesqui- 

 oxide 6-4, alumina 6 1. From Arendal, Norway. 



Tscheffkinite. Near Keilhauite. From the Ilmen Mountains. 



Staurolite. — Staurotide. 



Trimetric. /A/=129° 20'. Cleavage imperfect. Usual- 

 ly in cruciform twin crystals. Fig- 2. 

 * ure 2 is a common kind ; another 



crosses at an acute angle near 60° ; 

 and another, of rare occurrence, con- 

 sists of three crystals intersecting at 

 angles near 60°. Never in massive 

 forms or slender crystallizations. 

 Color dark brown or black. Lustre vitreous, inclining 

 to resinous ; sometimes bright, but often dull. Translu- 

 cent to opaque. H. = 7-7 0. G. =3-4-3-8. 



Composition. H,K 3 A1 6 34 Si 6 = Silica 30*37, alumina 51*92, 

 iron protoxide 13*66, magnesia 2*53, water 1*52 = 100. B.B. 

 infusible. Insoluble in acids. 



Diff. Distinguished from tourmaline and garnet by its 

 infusibility and form. 



Obs. Found in mica slate and gneiss, in imbedded crys- 

 tals. 



Occurs very abundant through the mica schist of New 

 England : Franconia, Vt. ; Windham, Me. ; Lisbon, N. H. ; 

 Chesterfield, Mass. ; Bolton and Tolland, Ct. ; also on the 

 Wichichon, eight miles from Philadelphia ; at Canton, and 

 in Fannin County, Georgia. Mt. Campione in Switzerland, 

 and the Greiner Mountain, Tyrol, are noted foreign locali- 

 ties. 



