PHYSIOGRAPHY. 27 



Anthopbyllite. 



Primary form. Oblique rhombic prism. P on P x = 

 125. 



Cleavage parallel to the sides of the primary form and 

 both its diagonals, the cleavage parallel to the longer di- 

 agonal being more distinct and easily obtained. 



Fracture uneven. 



Surface streaked parallel to the axis. 



Lustre pearly, inclining to metallic, particularly upon the 

 perfect face of cleavage. Qolor between yellowish-grey 

 and clove-brown. Streak white. Translucent, sometimes, 

 only on the edges. 



Brittle. Hardness = 5-0 . . . 5-5. Sp. gr. =3-129. 



Compound Varieties. Massive ; composition columnar, 

 straight, sometimes divergent and rather broad ; faces of 

 composition irregularly streaked. They are often aggre- 

 gated in a second composition, which is angulo-granular 

 and wedge-shaped. 



1. Alone before the blow-pipe, it is unalterable except in very thin 

 fragments, when it fuses on the edges into a black slag. With borax, it 

 melts with difficulty into a glass, colored by iron. 



2. Analysis. 



By JOHW. By THOMSOX. By GMELIN. 



Silica 56-00 56-290 - 56-00 



Alumina - 13-30 1-545 - 3-00 



Magnesia - 14-00 19-665 - 23-00 



Lime 3-33 0-000' - 2-00 



Oxide of iron 6-00 7-280 - 0-00 



Oxide of manganese 3-00 0-000 - 4-00 



Water 1-43 1-685 - 0-00 



Potash 0-00 13-500 - 12-00 



3. Anthophyllite occurs in beds of mica-slate, accompanied by Gar- 

 net, Talc, Augite, lolite, &c. 



4. It has been brought from the cobalt and copper mines of Kongsberg 

 and Modum in Norway. It is found with Augite in Greenland ; and 



