SULPHIDES, ARSENIDES, ANTIMOMD1 s 



tions, though it may be said there is great doubt of this in case of the 

 Sudlmry deposit. In these localities pyrrhotite is associated with 

 py rite, chalcopyrite, and other minerals, \vhich are the results of oxi- 

 dation. Pyrrhotite may also result from pneumatolytic action, as 

 by the interaction of hydrogen sulphide and ferric chloride. 



In addition to the localities mentioned above, pyrrhotite occurs 

 at Standish, Maine, in crystals ; in Essex County, New York ; at 

 the Gap mine, Pennsylvania; in North Carolina and Virginia; 

 large tabular crystals are obtained from Minas Geraes, Brazil. 



Artificially pyrrhotite may be formed by the reaction of H 2 S 

 on iron at a high temperature and under pressure; in the wet way 

 by heating a solution of FeCl 3 , NaiCOs, and H 2 S, for a considerable 

 time at 200 C. in a closed tube with all air excluded, otherwise 

 pyrite will form ; also by the action of H 2 S on slightly acid solu- 

 tions of ferrous salts containing some ferric salts between the 

 temperatures of 80 and 225. 



NICCOLITE 



Niccolite. Copper nickelj NiAs, Arsenide of nickel; Ni = 

 43.9, As = 56.1 ; 0001 A lOll = 43 25'. Hexagonal ; Type, 

 Hexagonal Polar (?) c = 0.8194 ; Common forms, c (0001), m (1011) ; 

 Cleavage, doubtful ; Brittle, fracture uneven ; H. = 5-5.5 ; G. = 

 7.33-7.67; Color, pale copper-red; Streak, brownish black; 

 Luster, metallic. 



B.B. Fuses easily on coal to a brittle globule and yields an 

 arsenical odor, with fumes of AssOs and possibly a white coat of 

 oxide. Well roasted and treated with borax on coal yields a per- 

 sistent nickel reaction. Soluble in hot nitric acid. 



General description. Crystals very rare, usually massive or 

 disseminated ; when fresh, the color is very characteristic but 

 tarnishes to black. Isomorphous with CoAs, NiSb, and FeAs, all 

 of which it may contain in small quantities, and these metals will 

 show in the first portions of borax when testing on coal for the bead 

 colorations. 



Breithauptite, NiSb, is the very similar antimony compound 

 associated with niccolite at the mines at Freiberg, Saxony; An- 

 dreasberg in the Harz ; and at Cobalt, Ontario. At the latter 

 locality there is a remarkable deposit of cobalt, nickel, and silver 

 ores, filling veins, fissures, and the joints in a metamorphosed rock 



