ORDER VIII. UNCLEAVABLE UKANIUM-ORE. 393 



GENUS VII. URANIUM-ORE. 

 1. UXCLEAVABLE URANIUM-ORE. 



Indivisible Uranium or Pitch-Ore. JAM. Svst. Vol. III. 

 p. 178. Uncleavable Uranium-Ore. Man. p. 241. 

 Uran-Ochre. Pitch-blende. PHILL. p. 2(7- Pecherz 

 (Uranpecherz). WERN. Hoffm. H. B. IV. 1. S. 271. 

 Pechuran. HAUSM. I. S. 325. Uran-Pecherz. LEOXH. 

 S. 308. Urane oxydule'. HAU Y. Traite', T. IV. p. 280. 

 Tabl. comp. p. 113. Traite', 2de Ed. T. IV. p. 316. 



Regular forms and cleavage unknown. Fracture 



conchoidal, uneven. 



Lustre imperfect metallic. Colour greyish-black, 

 inclining sometimes to iron-black, also to green- 

 ish- and brownish-black. Streak black, a little 

 shining. Opake. 

 Brittle. Hardness = 5-5. Sp. Gr. = 6-468. 



Compound Varieties. Reniform : composition 

 columnar, impalpable ; aggregated into a second 

 curved lamellar composition, the faces of composi- 

 tion being smooth and shining. Massive : compo- 

 sition granular, individuals not distinguishable. 



OBSERVATIONS. 



1. The analysis of a variety of the present species yield- 

 ed to KLAPROTH, 



Protoxide of Uranium 86-50. 



Protoxide of Iron 2-50. 



Silica 5-00. 



Sulphuret of Lead 6-00. 



Alone it is infusible before the blowpipe, but it melts with 

 borax into a grey scoria. If reduced to powder, it is slow- 

 ly soluble in nitric acid. 



2. The uncleavable Uranium-ore chiefly occurs in silver 



