96 THE MINERALS OF CHILE. 



Horn Silver, Chloride of Silver. — This is one of the most ahunclant silver minerals in Clule^ 

 as it is found there in quantities far exceeding anything that is elsewhere known. It is com- 

 monly massive, resembling wax of a grayish color, when the surface is freshly broken; but soon 

 tarnishes on the exposure to light, acquiring a purplish tint. Sometimes it is of a greenish 

 tint. Its lustre is resinous; easily cut with a knife; sp. gravity 5.4. It possesses all the 

 properties of the artificial chloride. Its composition is — 



Silver -.-_... 75.33 

 Chlorine - 24.67 



100.00 



Formula, Ag CI. 



Several very fine specimens were brought by the expedition from the Chaiiarcillo, Valenciana 

 mines, in Atacama, and other localities. 



Bromic Silver. — This compound of silver is likewise found in Chaiiarcillo, and in many 



respects resembles the chloride ; its color is greener, and it never occurs in such masses as the 



chloride. It is equally soft, having a little higher specific gravity — 5.8. Composition when 



pure — 



Silver -_._--. 53 



Bromine ------- 42 



100 

 Formula, Ag Br. 



Embolite, CMoro-hromide of Silver. — This mineral is found both crystallized and massive in 

 several of the mines of Chile, in the provinces of Atacama and Coquimbo. It is less abundant 

 than the chloride, although more so than the bromide. Externally it is greenish, internally a 

 sulphur-yellow ; it has the same lustre as the chloride ; it is, however, harder than the latter ; its 

 specific gravity is the same as the bromide. The composition of it is — 



Silver ------- 66.96 



Chlorine ------- 13.20 



Bromine ------- 19.84 



100.00 



Formula is, Ag (CI Br.) 



Iodic Silver. — This beautiful and rare mineral has been found in some little quantity in the 

 silver mines of Algodones, province of Coquimbo. The mineral is of a pale, sulphur-yellow 

 color, very fragile and soft, having a specific gravity of 5.5. One specimen that I saw had 

 crystalline faces, indicative of a rhombic dodecahedron. It is commonly lamellar, and M. 

 Domeyko has recognised in some small pieces three rhomboidal cleavages ; two of the cleavages 

 appear quite perfect, having a pearly lustre. It is more brittle and more fusible than either 

 the chloride or the chloro-bromide. The presence of iodine and silver are readily recognised 

 by the ordinary tests. Its gangue is composed partly of carbonate of lime and partly of a brick- 

 red fine clay. In the Carmen mine, a considerable amount of iodide was found in the first 

 part of the vein ; at the depth of twelve varas (33 feet) it disappeared, and chloro-bromide 

 made its appearance in identically the same gangue ; and at a still greater depth the latter 

 mineral disappeared, and was rejilaced by the chloride, accompanied with the sulphuret of 

 silver. It has also been found in small quantities at one of the mines of the Chaiiarcillo district. 



This interesting mineral has the same atomic constitution as the other natural haloid salts of 

 silver, as originally shown by M. Domeyko ; although, in referring to certain works on miner- 

 alogy, Domeyko is quoted as giving for its composition one atom of silver and two of iodine, 

 while the chloride and bromide of silver are alluded to as constituted of atom and atom, forget- 



