Sulphuret of Silver

Sulphuret of Silver has been so sparingly found in Britain, that very few cabinets possess specimens of it; in such as have beeu found it is generally irregularly disseminated among Quartz, Gahena, and Arsenical Pyrites, in a decomposing state, with filamentous Native Silver; such specimens I have from Herland Mine in Cornwall. The crystallized ones now figured are in the possession of Mr. Galley, who obtained them from Huel Dutchy: the upper one has many small eubo-octohedrons, and part of it is covered with a film of pyrites: in the lower specimen the Sulphuret of Silver is accompanied by Hair Silver and Quartz ; many of the Crystals are regular cubo oetoheclrons, but several are so much elongated or compressed, that although derived from the same form the faces are difficult to trace. The characters by which this ore may be discovered, are, its texture, between that of hard wax and lead, colour blacker than lead, with a slight metallic lustre: before the blow-pipe a globule of silver may be obtained.

There is another Silver ore rarely found in the mines of Cornwall, the Red or Antimonial Sulphuret of Silver, figured in Exotic Mineralogy, tab. 33; but the specimens are by no means sufficiently characterized for illustration by a figure. I published both these ores of Silver in Exotic Mineralogy at the same time when I had not seen a British specimen of either.