PYROXENE. 15] 



Sahla, where it occurs. Fassaite ; in crystals of rich green 

 shades and smooth and lustrous exterior. The name is de- 

 rived from the foreign locality Fassa. Alalite ; a diopsido 

 from Piedmont. Coccolite is a general name for granular 

 varieties, derived from the Greek coccos, grain. The green 

 is called green coccolite, the white, white coccolite. The 

 specific gravity of these varieties varies from 3*25 to 3*3. 



Composition : silica 55*3, lime 27*0, magnesia 17*0, pro- 

 oxyd of manganese 1*6, protoxyd of iron 2*2. Fuse before 

 he blowpipe to a colorless glass ; with borax or soda form a 

 ransparent glass. 



Asbestus. This name includes fibrous varieties of both 

 pyroxene and hornblende ; it is more particularly noticed 

 under the latter species. 



II. Augite includes black and greenish-black crystals, 

 mostly presenting the form figured above. Specific gravity 

 3*3 — 3*4. Hedenbergite is a greenish-black opaque variety, 

 in cleavable masses affording a greenish-brown streak. 

 Specific gravity 3 '5. Polylite, Hudsonite, and Jeffersonite 

 fall here. 



The varieties in this section contain a large proportion of 

 iron, or iron and manganese. Composition of one variety, 

 silica 54*1, lime 23*5, magnesia 11 "5, protoxyd of iron 10*0, 

 protoxyd of manganese 0*6 = 99*7. Fuse like the prece- 

 ding, but the globule obtained is colored with iron. 



III. Diallage is a thin -foliated, clear green variety, occur- 

 ring imbedded in serpentine ; folia thin, brittle, translucent. 

 Bronzlte occurs in serpentine and greenstone, and is similar- 

 ly ibliated ; its colors are dark green, or greenish brown, 

 with a metallic-pearly luster, or like bronze. Specific grav- 

 ity 3 # 25. Hypersthene is less thinly foliated than bronzite, 

 but cleaves readily ; color grayish or greenish black, and 

 luster metallic-pearly, Gr=3* 39. The Labrador hornblende, 

 and Metalloidal diallage are here included. 



Composition of hypersthene, silica 54*25, lime 1*5, magne- 

 sia 14*0, protoxyd of iron 24*5, protoxyd of manganese a 

 trace, alumina 2*25, water 1*0. The edges fuse with diffi- 

 culty to a grayish green semi-opaque glass ; some varieties 

 wholly fuse. Other hypersthenes contain much less iron and 

 large proportion of lime. 



Dif. Resembles hornblende, but is distinct in cleavage 



What is coccolite 1 What is the appearance of asbe9tus ? What 

 s diallage? What is hypersthene ? 



