404 ' REPORT OF NATIONAL MUSEUM, 1899. 



lenticular mass in one of the ordinary gold-bearing lodes traversing 

 the gneiss and mica schists of the district. The body occurred some 

 60 feet below the surface and was some 30 feet long by 10 feet deep 

 and 10 inches thick. The mass yielded some 4 tons of ore carrying 

 70 per cent oxide of uranium. 



Other natural uranium compounds, but which at present have no use 

 in the arts, are as below: Torbernite, a hydrous phosphate of uranium 

 and copper; autunite, a hydrous phosphate of uranium and calcium; 

 zeunerite, an arsenate of uranium and copper; uranospinite, an arse- 

 nate of uranium and calcium; uranocircite, a phosphate of barium and 

 uranium; phosphuranylite, a hydrous uranium phosphate; trogerite, 

 a hydrous uranium arsenate; walpurgite, probably an arsenate of bis- 

 muth and uranium; and uranosphserite, a uranate of bismuth. 



Carnotite is a recently described uranium compound containing, 

 according to analyses, some 52 per cent uranium oxide (UO 3 ); 20 per 

 cent of vanadium oxide (V 2 O 5 ), and 11 per cent of potash. It is of a 

 beautiful light lemon-yellow color and of an earthy or ocherous texture. 

 According to descriptions gleaned from correspondence, and from sam- 

 ples received at the U. S. National Museum (Specimens Nos. 53491, 

 53492, 53649, U.S.N.M.), the material occurs mainly as an impregnation 

 in the form of an extremely fine, crystalline powder in the Dakota sand- 

 stones in the vicinity of La Sal Creek and Roc Creek, Montrose 

 County, and near Placerville, San Miguel County, Colorado. 1 



Uses. Uranium is never used in the metallic state, but in the form 

 of oxides, or as uranate of soda, potash^ and ammonia, finds a limited 

 application in the arts. The sesquioxide salt imparts to glass a gold 

 yellow color with a beautiful greenish tint, and which exhibits remark- 

 able fluorescent properties. The protoxide gives a beautiful black to 

 high-grade porcelains. The material has also a limited application in 

 photography. Recently the material has been used to some extent in 

 making steel in France and Germany, but the industry has not yet 

 passed the experimental stage. It has been stated that the demand, all 

 told, is for about 500 tons annually. Should larger and more constant 

 sources of supply be found, it is probable its use could be considerably 

 extended. According to Nordenskiold, 50,000 worth of uranium 

 minerals are consumed every year, the various salts produced being 

 used in porcelain and glass manufacture, in photography, and as chem- 

 ical reagents. 8 



1 Since the foregoing was written Mr. W. F. Hillebrand, of the U. S. Geological 

 Survey, has published (American Journal of Science, Vol. X, 1900, pp. 120-144) the 

 results of an exhaustive study of the material from this and other localities, and 

 shows that the so-called carnotite is probably a mixture of minerals made up to a 

 large extent of calcium and barium compounds intimately mixed with amorphous 

 silicates containing vanadium in the trivalent state. 



2 Quarterly Journal of the Geological Society of London, LVI, 1900, p. 527. 



