Sulphuret of Silver, or Vitreous Silver ore

I am indebted to the kindness of W. E. Rundellj Esq. for the larger specimen of this substance. It is composed of uncommonly large octaëdral crystals. The smaller one is from the collection of Wilson Lowry, Esq.; its crystals are elegantly supported by equiaxed crystals of Carbonate of Lime.

This mineral occurs in veins in various Silver Mines, as those of Hungary, Germany, Peru, Mexico, &c.

The colour appears very dark lead grey, when fresh broken; by exposure, the surface becomes tarnished. It is very opaque, with a metallic lustre, very soft, ductile, and pliable; the Spec. Grav. is from 6.909 to 7.215. A red heat dissipates the Sulphur, and leaves the Silver: if this experiment be tried with care, the Silver is protruded in filaments from the mass. A heat a little above redness melts it, and requires to be continued a considerable time, to separate the whole of the Sulphur.

The usual crystals of this ore are the cube and the octaëdron, often variously truncated or bevilled. Spec. Grav. 6.909 to 7.215. Gellert