BISMUTH. 25g 



Octahedrisches Wismuth, Mohs. — Its colour is silver-white, occa- 

 sionally tinged with red ; the lustre is metallic and splendent. It 

 is seldom massive generally disseminated, in plates having plum- 

 osely-streaked surfaces, reticulated, and crystalized. The crystals 

 are regular octahedrons, which is the primitive form, acute rhom- 

 boids, (fig. a,) cubes, and tetrahedrons. Its specific gravity is 9'02. 

 Its fracture is foliated, with a cleveage in three directions : it is soft, 

 sectile, and somewhat malleable. It is very fusible, and melts 

 even in the flame of a candle. Before the blow-pipe it is vola- 

 tilized, in the form of white vapours, which have an arsenical 

 odour. It dissolves with effervescence in nitric acid, and the 

 solution is decomposed when water is added, and a white preci- 

 pitate is formed. This precipitation of the nitric solution by the 

 addition of water, is the distinctive character by which bismuth is 

 distinguished from most other metals. It occurs in vein6 in pri- 

 mitive rocks in Cornwall, and other mining districts in Europe 

 and North America, but its chief localities are at Joansreorsenstadt 

 and Schneeberg in Saxony, from whence the supply of Bismuth in 

 commerce is principally obtained. To procure the metal, the ore 

 merely requires to be reduced to small fragments and exposed to a 

 moderate heat in a furnace, with a quantity of reducing flux, when 

 the bismuth separates from the earthy matter in which it is disse- 

 minated, and flows out into cast iron moulds prepared for its 

 reception. 



Sp. 2. Sulphuretted Bismuth, or Btsmuth Glance. — 

 Wismuth Glanz, Werner; Prismatischer Wismuth Glanz, Mohs.; 

 Bismuth sulfure, Haiti/. — Its colour is pale lead-grey. It occurs 

 amorphous, in granular and radiated concretions, and crystalized 

 in oblique four-sided prisms. The fracture is foliated, and ft is 

 divisible into slightly rhomboidal prisms. The lustre is splendent 

 and metallic. It is sectile, brittle, easily frangible, soft, and soils 

 the fingers. The specific gravity is from G-l to 6*4* It melts in 

 the flame of a candle. Its constituents are bismuth 60, sulphur 40- 

 It is rather a rare mineral ; and chiefly occurs in veins traversing 

 primitive rocks in various parts of Cornwall ; in granite at Car- 

 rock-fell in Cumberland, and other countries. 



Ackular Bismuth, Ph/wbo-cuprcous Bismutli or Needle-ore. 



