ALUMINA. 



333 



Putnam County. Small, white, somewhat rounded and opaque crystals of scapolite, asso- 

 ciated with sphene, apatite, quartz, etc., are found in the white limestone at Hustis' farm 

 and elsewhere in Phillipstown. The forms are the primary and the eight-sided prism, but 

 they are seldom perfect. 



St. Lawrence County. Scapolite, both crystallized and massive, occurs in the white 

 limestone in the vicinity of the village of Gouverneur. It is associated 

 with apatite, sphene and pyroxene. The crystals are white, translucent 

 to semi-transparent, and possess a high degree of perfection and finish. 

 The forms observed are the primary (Fig. 279) ; the dioctaedre of Haiiy, 

 usually with the prism very short, as in Fig. 299 ; and a modification of 

 Fig. 293, the prism having only ten, instead of twelve, lateral planes. 



Fig. 299. 



STAUROLITE. 



[From the Greek rfraupof, a cross, and Xi^o?, a stone ; on account of the cruciform appearance of its 



compound crystals.] 



Staurotide. Hqii/tj, Ckaveland, Thomson, Beudant and Skepard. — Staurolite. Phillips. — Prismatoidal Garnet, 

 or Grenatite. Jaineson. — Prismatoidischer Granat. Mohs. — (Called also Pierre de Cfoix.) 



Fig. 300. Description. Colour dark reddish brown, sometimes almost black. 



Streak white. It always occurs crystallized. Primary form a right 

 rhombic prism. Fig. 300. M on M' 129° 30'. The acute lateral edges 

 are often replaced by planes, forming a six-sided crystal. Cleavage 

 parallel to o (Fig. 301) perfect ; traces in the direction of M. Fracture 

 conchoidal, uneven. Lustre vitreous, inclining to resinous. Ranges 

 from translucent to opaque. Hardness 7.0 to 7.5. Specific gravity 

 from 3.20 to 3.90. Before the blowpipe it is infusible, or difficultly 

 fusible in a black scoria ; with borax, it melts slowly into a transparent 

 deep green coloured glass. 

 The form and infusibility distinguish this mineral from garnet, with which it is usually 

 associated. 



Composition. Silica 48.00, alumina 40.00, lime 1.00, oxide of iron 9.50, oxide of man- 

 ganese 0.50 {Decotils). 



Geological Situation. In this State, staurolite is always found in gneiss or mica slate. 



LOCALITIES. 



Dutchess County. Staurolite is found associated with garnet, in mica slate, at the Foss 

 iron ore bed in the town of Dover. The crystals are usually small, and are of the primary 

 form (Fig. 300) ; the primary with the acute lateral edges replaced by tangent planes, peri- 



