Silver. 



SPECIES XV. 



Mineralized by the Vitriolic and Marine ActJs, 

 'with a little Iron> and fomeiimes 'with a 

 mixture of the Vitreous Ore. 



Corneous Sifoer Ore, Horn ertz. 



31. This fcarce and valuable ore is of a 

 white, grey, pearly, or yellow, green, brown, 

 purple, or black colour, frequently cryftalized 

 in a cubic form, fometimes refembling an. 

 Earth, eafily fufible without any fmoke. 

 The black fort is friable, and eafily pulve- 

 rifed, but the other fort is in fome degree 

 malleable, may be cut with a knife, and takes 

 a fort of polifh when rubbed. The vitreous 

 ore mixed with the black, is foluble in nitrous 

 acid, and may by that means be feparatecj* 

 the faline ores being infoluble in that acid ; 

 if pure from iron, thefe ores fliould contain 

 70 per cent of filver at leaft, but they moftly 

 contain fome portion of iron, of which foma 

 is even united to the marine acid according to 

 Monnet. It is found in Saxony^ Bohemia, S/v 

 Marie aux Mines, Siberia^ and Peru. It was 

 firft eflayed by Mr. Wolfe, Phil. Trans. 1776, 

 and afterwards, though lefs exaclly, by Mr* 

 Monnet, in 1777? fee 9 Mem. Etr. p. 717, 



32. Mr, 



