OF CENTRAL CANADA PART II. 89 



D. URANIUM OXIDES. 



37. Uran Ochre : Yellow, in earthy crusts. BB, blackens, but 

 does not fuse. Composition, probably, sesquioxide of uranium and 

 water. In Canada, observed only as a coating on magnetic iron ore 

 with intermixed actynolite, at the Seymour Mine in Madoc. 



38. Black Uranium Ore or Pitch-blende (Coracite, &c.) : Black, 

 greyish-black, greenish-black, with greyish or brownish streak. 

 Aspect between sub-metallic and vitreo-resinous. Mostly in nodu- 

 lar or other imcleavable masses. H = 5.5 when pure, but frequently 

 less from intermixed earthy matters ; sp.gr. 6.6 7.0 when pure, 

 but sometimes as high as 8.0, and often only 4.0 or 4.5, from impuri- 

 ties. BB, infusible, or rounded only on the thinnest edges. Com- 

 position, normally, protoxide of uranium 32.10, sesquioxide 67.90; 

 but, in many instances mixed with carbonate or silicate of lime, 

 lead, bismuth, copper and other compounds. 



The only known locality in which this substance occurs in Canada, 

 is at Maimanse, on the east shore of Lake Superior. The variety 

 found at this spot was first described by Dr. Le Conte under the 

 name of Coracite. It is mixed with carbonate of lime and other 

 impurities, by which its sp. gr. is reduced to between 4.3 and 4.4 

 (4.378 Le Conte), and its hardness to about 3.5 or 4.0. It yields 

 also, according to the analyses of Whitney and Genth, about 5 or 6 

 per cent, of water (Dana's Mineralogy : 5th ed. p. 155). 



E. TUNGSTENUM COMPOUNDS. 



39. Wolfram : Brownish -black, with strong, sub-metallic lustre, 

 and blackish-brown or red-brown streak. Rhombic in crystalliza- 

 tion, but occurring frequently in irregular masses of lamellar or 

 columnar structure. H=5. 05.5; sp.gr. 7.1 7.6. BB, melts 

 into a dull iron-grey globule with striated or crystalline surface. 

 Consists of Tungstic acid combined with oxides of iron and mangan- 

 ese. 



The only known examples of Canadian wolfram, were found by 

 the writer, some years ago, in a large boulder of gneiss, on the north 

 shore of Chief's Island, Lake Couchiching. (See description in 

 Canadian Journal, 2nd series, Vol. 1. p. 308. Also, for analysis by 

 Dr. Sterry Hunt, Vol. V., p. 303\. 



F. TITANIUM OXIDES. 



[See also Ilmenite and Iserine under the Iron Ores.] 



40. Rutile: D irk-red, with peculiar adamantine lustre: streak, 



