PYROXENE. 15 1 



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. ,j 

 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 noticedj 

 under the latter species. 



II. Augite includes black and greenish-black crystals, \ 

 mostly presenting the form figured above v 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. 

 2$r->*i->te occurs in serpentine and greenstone, and is similar- 

 ly lo.iated ; 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-pearlyJGr=3* 39. The Labrador Jiornblende, 

 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 

 wholl) fuse. Other hypersthenes contain much less iron and 

 large proportion of lime. 



/Dif. Resembles hornblende, but is distinct in cleavage 

 s 

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

 s diallage? What is hypersthene ? 



