SILVER. 443 



and small filaments of the same metal have undoubtedly been obtained at the Bridgewater 

 copper mines in New-Jersey. 



VITREOUS SILVER. 



Argent Sulfnre. Hatiy. — Sulphuret of Silver. Cleavdand, Phillips and Thomson. — Vitreous Silver. Shepard. — 

 Hezahedral Silver-Glance. Jameson. — Hexaedrischer Silber-Glanz. Mohs. — Argyrosc. Beudant. 



Description. Colour blackish lead-grey, with occasionally an iridescent tarnish. Streak 

 shining. It occurs regularly crystallized, most frequently in cubo-octahedrons ; also massive, 

 disseminated, in plates or leaves, filiform, capillary, dentritic, reticulated, etc. The primary 

 form is a cube. Traces of cleavage sometimes observable parallel to the faces of the rhombic 

 dodecahedron. Fracture uneven, sometimes flat conchoidal. Lustre metallic. Opaque. Mal- 

 leable. Flexible, but not elastic. Hardness from 2.0 to 2 . 5. Specific gravity from 6 . 90 

 to 7 . 20. Before the blowpipe, it intumesces, the sulphur is driven off, and a bead of pure 

 silver remains. It is soluble in nitric acid, and may be precipitated in the form of metallic 

 grains upon a clean plate of copper. 



Composition. Silver 87.05, sulphur 12.96 {Berzelius). Formula AgS. 



Geologicai Situation. It occurs chiefly in veins in gneiss, mica slate and greywacke, 

 associated with ores of silver, lead and antimony, blende, p)nrites and calcareous spar. It is 

 abundantly met with in Mexico, and most of the silver obtained from the celebrated mines of 

 Guanaxuato is extracted from this ore. A black decomposed variety known by the name of 

 Silver black, often accompanies this mineral. 



localities. 

 This species is said to have been found at Livingston's lead mine in Columbia county. It 

 is probable also that it exists in those varieties of galena which yield silver by the process of 

 cupellation, as those of Sullivan county. 



