SI l.K 'ATI'S, TITANATES, ETC. 



and stout combinations of m, b, r, and t; the pinacoid a is never 

 well developed. On the surface these crystals appear as if cor- 

 roded, caused probably by magmatic resorption. The character- 





/ 



FIG. 476. Actinolite in Talc, from the Tyrol. 



istic cleavage of approximately 124 serves to distinguish them from 

 the pyroxenes. Color varies greatly with the composition, being 

 white or gray in tremolite, where there is little or no iron ; green in 

 actinolite; black or dark brown in the basaltic hornblende; and 



** "' 



FIG. 477. Fibrous Amphibolc : Var. Asbestos from the Tyrol. 



pink in hexagonite, a manganese variety. The soft, fibrous variety 

 is asbestos and differs from the serpentine variety of asbestos, as 

 it contains no water. In sections it is irregular, granular, or 



2F 



