SURSILICATES. 291 
and pyroxene, at Gouverneur, near Natural Bridge in Lewis 
County (the variety called Leder ite); in Orange County in 
Monroe, Edenville, Warwick, and Amity : near ” Peekskill i 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 290, yttria 9-6, lime 18°9, iron sesqui- 
oxide 6:4, alumina 6-1. From Arendal, Norway. 
Tscheffkinite. Near Keithauite. From the Ilmen Mountains. 
Staurolite.—Staurotide. 
Trimetric. JA 2=129°20'. Cleavage imperfect. Usual- 
il 
ly in cruciform twin crystals. Fig- 
ure 18 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.=7-7'5. G.=3-4-3°8. 
Composition. TRA, Ox Sig= Silica 30°37, alumina 51°92, 
iron protoxide 13°66, magnesia 2°53, water 1°52=100. B.B. 
infusible. Insolubie 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. 

