PHYSIOGRAPHY. 107 



Pitchblende. 



2. It occurs in a vein of Heavy Spar, in the mine of Neu Beschert 

 ldck, in the mine of Saxon Erzgebirge, and at Geilsdorf in Plauen. 



FINITE. (See Mica.) 



PlSSOPHANE. 



Stalactitic, massive, anil impalpable. Fracture conchoidal. 



Lustre vitreous. Color pistachio- green, aspttragus-green, and 

 olive-green, passing into brown. Streak white ; in the brown 

 variety, a pale yellow. Transparent to translucent. 



Hardness = 1-75 . . . 2-50. Sp. gr. = 1-92 . . . 1-98. 



It falls to pieces in water. 



1. It occurs at Reichenbach, and in Garnsdorf. 



ITCHBLENDE. Uncleavable Baryte-Ore. 



Regular forms and cleavage, unknown. Fracture con- 

 hoidal, uneven. 



Lustre imperfectly metallic. Color greyish-black, incli- 

 ning sometimes to iron-black, also to greenish black and 

 brownish black. Streak black, a little shining. Opake. 



Brittle. Hardness = 5*5. Sp. gr. = 6-4b8. 



Compound Varieties. Reniforrn : composition colum- 

 |nar, impalpable ; aggregated into a second curved, lamel- 

 lar composition, the faces of composition being smooth and 

 shining. Massive : composition granular, individuals not 

 Distinguishable. 



1. Alone, before the blow-pipe, it is infusible, but it melts, with borax 

 into a greyish scoria. If reduced to powder, it i slow))' soluble in mtric 



acid. 



2. Analysis. 



By KLAPROTK. By PFAFF. 



Protoxide of uranium . 8650 .... 84-52 

 Protoxide of iron . 250 .... 824 



Silica . 500 .... 2-02 



Sulphuretoflead . 600 .... 4-20 



Oxide oi cobalt 0-00 . . . . 1-42 



