t2 



SILVER. 119 



Dyscrasite, or Antimonial Silver, consists simply of silver and anti- 

 mony (78 parts to 22=Ag 4 Sb), and has nearly a tin-white color. 

 G. — 9'4-9'S. B.B. fumes of antimony pass off, leaving finally a 

 globule of silver. From Wolfach, Wittichen, Andreasberg ; also 

 Allemont in Dauphiny ; and Bolivia, S. A. 



Pyrargyrite. — Ruby Silver. Dark Red Silver Ore. 



Rhombohedral. RaR = 108° 42 ; Bai-2 = 129° 39'. 

 Cleavage parallel to R imperfect. Also massive. Black to 

 dark cochineal-red, with the streak cochi- 

 neal-red and lustre splendent metallic-ada- 

 mantine. H. = 2-2 -5, G. = 5 -7-5 -9. 



Composition. Ag 3 S 3 Sb (=3 Ag 2 S + Sb 2 

 S 3 ) = Sulphur 17*7, antimony 22*5, silver 

 59-8 = 100. 



B. B. fuses very easily ; on charcoal a 

 white deposit of antimony oxide is deposited, 

 and with soda a globule of silver is obtained. In an open 

 tube gives off sulphurous fumes that redden litmus paper. 



Biff. Its red streak, and its reactions for antimony and 

 silver, are distinctive. 



Obs. Occurs at Andreasberg ; also in Saxony, Hungary, 

 Cornwall, Mexico, Chili ; in Nevada at Washoe ; abundant 

 about Austin, Reese River ; at Poor Man's Lode, Idaho. 



Proustite, or Light Red Silver Ore, is a related ore con- 

 taining arsenic in place of much or all of the antimony. 

 Composition, Ag 3 S 3 As = Sulphur 194, arsenic 15*1, silver 

 65-5 = 100. G. =5-4-5-56. 



B.B. gives a garlic odor. 



Occurs with pyrargyrite at the above-mentioned localities. 



Stephanite. — Brittle Silver Ore. Black Silver. 



Trimetric. I/\ 7=115° 39'. No perfect cleavage. Often 

 in compound crystals. Also massive. Streak and color 

 iron-black. H. =2-2-5. G. = 6-27. 



Composition. Ag 5 S 4 Sb ( = 5 Ag 2 S + Sb 2 S 3 ) = Sulphur 

 16*2, antimony 15*3, silver 68*5. B.B. it gives an odor of 

 sulphur and also fumes of antimony, and yields a dark 

 metallic globule, from which silver may be obtained by the 

 addition of soda. Soluble in dilute nitric acid, and the solu- 

 tion indicates the presence of silver by silvering a plate of 

 copper. 



