ARSENIC MINERALS O'Jl 



a. Fused with soda, yields a sulphur reaction on H!V<T. 

 + . Residue in K. !'. is magnetic. 



TENNANTITE, (Cu.Fe) 8 As,S7 ; C. Blackish gray ; Sir. 



Black to dark red; H. 3; G. 4.6; F. 1.5; p. 324. 

 Epigenite, 4 Cu 2 S, 3 FeS, AsS ; C. Steel-gray; Btr. 



I'-lack; H. 3.5; IV. 

 . Residue in R. F. is not magnetic. 



. With von KobelPs flux shows lead. 



Lengenbachite, Pb(Ag.Cu)AsS; C. Steel-gray; Str. 



Brownish, marks paper; G. 5.85. 

 ft. Shows no lead. 

 Binnite, Cu 6 As 4 S 9 ; 3 Cu 2 S.As2S 3 ; C. Iron-black; Str. 



Black; H. 2.5-3; G. 4.5; I. 

 Lautite, CuAsS; C. Iron-black; Str. Black; H. 3; 



G. 4.9. 

 6. Yields no sulphur reaction. 



Domeykite, Cu 3 As; C. Steel-gray; Str. Gray; H. 3-3.5; 



G. 7.5; G. 2; Massive. 

 Algodonite, Cu 6 As; C. Steel-gray; Str. Gray; H. 4; G. 



7.6; F. 2; Massive. 

 Whitneyite, CujjAs; C. and Str. Silver-white; H. 3.5; 



G. 8.5; F. 2; Massive. 



3. Roasted and then oxidized beside borax on coal, as directed 



in a, p. 574, it yields a strong cobalt reaction, 

 a. Fused with soda, yields a sulphur reaction. 



COBALTITE, CoAsS; C. Tin-white; Str. Black; H. 



5.5; G. 6-6.2; F. 2-3; p. 316. 

 GLAUCODOT, (Co.Fe) AsS; C. Gray; Str. Black; H. 



5; G. 5.95; F. 2-3. 

 6. Yields no sulphur reaction. 



SMALTITE, CoAsa; C. Tin-white; Str. Black; H. 



5.5-6; G. 6.3; F. 2.5; p. 315. 

 Safflorite, CoAsz ; C. Tin-white; Str. Black; H. 4.5-5; 



G. 7; F. 2.5; IV; p. 315. 

 Skutterudite, CoAs 3 ; C.Tin-white; Str. Black; H. 6; 



G. 6.75 ; F. 2.5 ; I ; p. 315. 



The nickel minerals and arsenopyrite below may at 

 times contain considerable cobalt. 



4. Roasted and treated beside borax as in 3, it yields a strong 



nickel reaction, with possibly the first three beads 

 colored with cobalt. 



