MINERALS OF CHILE. 69 



Light Ruby-silver. 



Silver 65.38 



Arsenic 19.46 



Sulphur 15.16 



The formula being 3 Ag S+As S 3 . 100 - 00 



The latter is the most common variety in Chile; one speci- 

 men, analyzed by M. Domeyko, furnished 



Silver , 63.85 



Iron .96 



Cobalt 19 



Arsenic 13.85 



Antimony 70 



Sulphur 18.00 



Gangue 1.60 



99.15 

 ANTIMONIAL SILVER. 



It is found both massive and crystallized near Coquimbo ; 

 it does not exist abundantly, is of a tin-white color with 

 metallic luster, having specific gravity of 9.5. This mineral 

 is frequently mixed with arsenical and native silver; when 

 pure it contains 



Silver 77 



Antimony 23 



Having for its formula Ag 4 Sb. 



POLYBASITE. 



Found in considerable quantity in the province of Atacama, 

 massive, of an iron-black color, and a specific gravity of 6.2 ; 

 it is composed of 



Silver 66.25 



Copper 4.08 



Arsenic 5.22 



Antimony 2.56 



Iron 2.34 



Sulphur 18.68 



99.13 

 Its formula is considered to be 9 (Ag Cu 2 ) S-f(Sb As) S 3 . 



BISMUTH-SILVER. 



In the mines of San Antonio, in the province of Copiapo, an 

 alloy of silver and bismuth is found; its color is tin-white, 



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