Copper. 263 



SPECIES IV. 



Mineralized by Sulphur withfcarce any Iron. 

 Vitreous Copper Ore, Kupfer glafe ertz. 



19. Its colour is red, brown, blue or violet ; 

 It is generally fo foft as to be cut with a 

 knife, and as to form, it is fometimes cryf- 

 talized in regular figures, and fometimes 

 amorphous; it is much more fuftble than 

 pure copper ; its fpecific gravity is from 4,81 

 to 5,338. It is found in the mines of other 

 copper ores, and in lime done, fpar, quartz, 

 mica and clay ; it is the richeft of all the 

 copper ores, and affords from 80 to 90 per 

 ceqt. of copper, i o or 1 2 of fujphur, with a 

 fmall proportion of iron ; the red ores are 

 the pooreft, containing moft iron. 



20. To analyfe this ore, Mr. Bergman ad- 

 vifes a folution of it in 5 times its weight of 

 concentrated vitriolic acid by ebullition to 

 drynefs and the fubfequent addition of as 

 much water as will diflblve the vitriol thus 

 formed. This folution he precipitates by a 

 clean bar of iron, and thus obtains the cop- 

 per in its metallic form. If the folution be 

 contaminated with iron, he re-diflblves thus 

 the copper thus obtained, in the fame manner, 

 and fo procures a richer folution, which he 

 again precipitates with iron. 



84 21. Dr, 



