SILVER. 247 



found in the greatest abundance in the mines of South America. 

 Native gold is distinguished from antimonial silver and native 

 antimony, by its hackly fracture, tenacity, and malleability, 



Sp.2. Antimonial Silver. Pl. XXXII. fig. 4.— Spieglas Silber, 

 Werner; Argent Antimonial, Hauy. hi. p. 391; Brong. ii. 249; 

 Antimonial Silver, Jameson, iii. p. 53. — Its colour is intermediate 

 between silver-white and tin-white ; the lustre is shining, but 

 frequently tarnished reddish or yellow externally ; internally 

 shining and splendent, with a metallic lusture. It generally occurs 

 massive, or in grains ; sometimes disseminated, globular, tuberose, 

 and crystalized. The most frequent crystalizations of this mineral 

 are the cube, the double six-sided pyramid, and the four- 

 sided or six-sided prism. The structure is laminar ; it is soft, 

 sectile in a slight degree, but is easily frangible. The specific 

 gravity varies from 9*40 to 1O00. According to Klaproth, the 

 constituents of the ore from Altwolfach are, silver 84, antimony 

 14 ; that from Andreasberg, silver, 754/, antimony 24-1. Antimo- 

 nial silver ore occurs in veins traversing granite, greywacke and 

 clay slate at Konigsberg, in Norway ; also in Spain, Germany, and 

 France. It is distinguished from native silver and white cobalt ore 

 by its sectility and foliated fracture, from arsenical pyrites by its 

 foliated fracture and inferior hardnes, 



Sp. 3. Arsenical Silver Ore. — Arsenik Silber, Werner; 

 Argent Antimonial Arsenifere, et ferrifere, Hauy, iii. p. 112; 

 Argent Arsenical, Brong. ii. p. 250 ; Arsenical Silver, Jameson, 

 iii. p. 76. Its colour on the fresh surface is tin-white, but tarnishes 

 greyish -black. — It is found massive, disseminated, globular, 

 reniform, and crystalized, in rectangular four-sided prisms. Its 

 fracture is imperfect foliated. It is harder than antimonial silver, 

 but is sectile, easily frangible, and the specific gravity is about 

 9 "44. The antimony and arsenic are volatalized before the blow- 

 pipe, with a garlic smell, and a globule of silver more or less pure 

 remains. Its constituents are, arsenic 35, iron 44*25, silver 

 12*75, antimony 4. It occurs in veins in primitive and transition 

 rocks, in Germany and Spain. 



Sp. 4. — Sulphuretted Silver, Vitreous Silver, or 

 Silver Glance. Pl. XXXIII. fig. 1. — Glaserz, Werner ; Argent 



