PHYSIOGRAPHY. 



Vitreous Copper. 



259 



Fig. 464. 



The inclination of P to P' is equal to that of the acute 

 terminal edge of a on a' on one side, and of 91 51' on 

 the other ; the respective inclinations of a on a! are 

 = 153 37', and =157 19'. Massive; composition 

 granular, of various sizes of individuals, generally small, 

 and often impalpable ; in the last case the fracture becomes 

 uneven, even or flat conchoidal. Plates. 



1. In the oxidating flame of the blow-pipe, it melts and emits glowing 

 globules, attended with some noise. In the reducing flame, it becomes 

 covered with a coat, and does not melt. When the sulphur is driven off, 

 a globule of copper remains. If the mineral be treated with nitric acid, 

 the copper is dissolved, forming a green solution; but the sulphur re- 

 mains undissolved. 



2. Analysis. 



By KLAPROTH. By UL.LMAJVN. 



Sulphur - - 18-50 - - 19-00 



Copper - - 78-50 - - - 79-50 



Iron 2-25 -' - - 0-75 



Silica - - 075 - - - 1-00 



3. It occurs abundantly in beds and veins, and is accompanied by 

 other ores of copper, by Iron-Pyrites and Quartz. 



4. Large and well defined crystals occur in several mines near Red- 

 ruth in Cornwall. Compound varieties, and rarely distinct crystals, are 

 found in beds in the Bannat of Temeswar, near Catherinenburg in Sibe- 



