MINERALS OF CHILE. 79 



AE8ENIURET OF IRON. 



This mineral is of metallic luster, of a silver-white color. 

 Specific gravity, 7.3. It is found in several of the silver-mines 

 of Chile, especially those of Oarriso, where it is accompanied 

 by mispickel, iron pyrites, blende, native antimony, ruby-silver, 

 and native silver. A specimen analyzed by M. Domeyko fur- 

 nished 



Arsenic 70.3 



Iron 27.6 



Sulphur 1.1 



Silver 2 



99 2 

 The formula is Fe As. 



MISPICKEL. 



Is found with copper and cobalt minerals near Coquimbo, 

 with copper and tungsten near Illapel, and with ruby-silver, 

 antimonial silver, and native silver in the mines of Chanarcillo, 

 in the lower part of the veins ; also near to Carriso. A speci- 

 men examined gave 



Arsenic 44.30 



Sulphur 20.25 



Iron 30.21 



Cobalt 5.84 



100.60 

 The formula of mispickel is Fe As-fFe S 2 , with cobalt re- 

 placing the iron to a greater or less extent. 



CARBONATE OF IRON AND MANGANESE. 



This is described as a distinct mineral by M. Domeyko, but 

 in all likelihood it is merely a mixture. It accompanies the 

 sulphuret of copper and gray copper in the silver-mines of San 

 Pedro Nolasco, in a formation of secondary stratified porphyry. 

 This species is of a dark blackish -gray and semi-metallic luster; 

 its structure is foliated in their laminae, diverging and grouped 

 together in such a manner that the whole forms globular con- 

 cretions, covered with small crystals of pearl-spar. The min- 

 eral is soft ; the powder is attracted by the magnet. It dissolves 

 readily in cold acids, and according to M. Domeyko's analysis 

 consists of 



