124 PHYSIOGRAPHY. 



Psilomelane Pyrallolite. 



The only European locality quoted, is Schneeberg, Saxony, though it 

 probably exists at several other places. Very well characterized speci- 

 mens are found in considerable quantity, at Chittenden, (Vt.) 



PURPLE COPPER. (See Phillipsite.) 

 PYCNITE. (See Topaz.) 

 PYKNOTROP. 



Massive : cleavage in two directions, but indistinct. Fracture 

 splintery. 



Lustre vitreous. Color greyish white, to brown and grey. 

 Translucent. 



Hardness = 2-5 . . . 3-0. Sp. gr. = 2-609 . . . 2-669. 



1. It is probably a vaiiety of Serpentine. 



PYRALLOLITE. Prismatic Tab ular- Sp ar. 



Primary form. Rhombic prism. M on M = 94 36'. 



Cleavage, distinct parallel to M, also to the diagonals of 

 the prism. 



Massive : composition granular. Fracture earthy. 



Lustre resinous. Color white, sometimes greenish. 

 Translucent on the edges . . . opake. 



Hardness =3*5 . . . 4*0. It seems to become harder by 

 exposure to the air. Sp. gr. 2'55 . . . 2-60. 



1. Before the blow-pipe, it first becomes black, then white ; after- 

 wards it intumesces and melts on its edges. With borax it yields a trans- 

 parent glass. When reduced to powder, it phosphoresces, with a bluish 

 light. 



