

C0B\LT ORES. 26* 



productive mines are those of Wehna, in Sweden, which were firs\ 

 opened in 1809. 



Cobalt pyrites is a sulphuret of cobalt, of a pale reddish or steel-gray 

 color. H=55. Gr=63 — 6*4. Crystals cubic. From Sweden, and 

 also Prussia; also Mine La Motte, Missouri. Named Lirinaiie. 



Another sulphuret of cobalt, with a less proportion of sulphur thar 

 in the last, has been observed in Hindostan. Color steel-gray, a little 

 yellowish. Named Syepoorite. 



earthy cobalt. — Black oxyd of Cobalt. 



Earthy, massive. Color black or blue-black. Soluble 

 in muriatic acid, with an evolution of fumes of chlorine. 



Obs. Occurs in an earthy state mixed with oxyd of man- 

 ganese, and in Missouri has been mistaken for black oxy i 

 of copper. It is quite abundant at Mine La Motte, Missouri 

 and also near Silver Bluff, South Carolina. The analyse? 

 vary in the proportion of oxyd of cobalt associated with the 

 manganese, as the compound is a mere mixture. Sulphuret 

 of cobalt occurs with the oxyd. The Carolina ores afforded 

 Dr. J. L. Smith, oxyd of cobalt 24, oxyd of manganese 76. 

 The ore from Missouri, as analyzed by Prof. Silliman, Jr., 

 afforded 40 per cent, of oxyd of cobalt, with oxyds of nickel, 

 manganese, iron and copper. It has also been detected 

 with hematite, in Chester Ridge, Pa. 



This ore has been found abroad in France, Germany, 

 Austria, and England, but much of it contains very little 

 oxyd of cobalt. 



Uses. The ore of Missouri is exported to England in large 

 quantities, and there purified and made into smalt, for the arts. 



erythrine. — cobalt bloom. — Arsenate of Cobalt. 



Monoclinic. In oblique crystals having a highly perfect 

 cleavage and foliated structure like mica. Laminae flexible 

 in one direction. Also as an incrustation, and in reniform 

 shapes, sometimes stellate. 



Color peach and crimson red, rarely grayish or greenish ; 

 streak a little paler, the powder dry lavender blue. Lus- 

 ter of laminae pearly ; earthy varieties without ..uster. Trans- 

 parent to subtranslucent. H = l*5 — 2. Gr=2*95. 



Composition : oxyd of cobalt 37*6, arsenic acid 88*4, wa- 



What is said of the black oxyd of cobalt? What is the appearance 

 and structure of cobalt bloom ? of what does it consist 1 



