107 



TAB. CCCLVIIL 



CUPRUM SulphureumArsenico-ferriferum. 



Arsenico-ferriferous, or Grey Sulphuret of 

 Copper. Fahl-ore* 



Class 3. Metals. Order 1. Homogeneous. 



Gen. 12. Copper. Spec. J. Arsenico-ferriferous sulphuret. 



Syn. Gray Copper Ore, Kirw. 2. 146. 

 Fahlerz. Emmerl. 2. 238. 

 Cuivre gris. Haiiy, 3. 537. 



Grey Copper has been found in several Mines in Corn- 

 wall. I have a neat little specimen in Tetraedrons from 

 Tavistock, in Devonshire, by favour of John Taylor, Esq. 



The present very neat specimen came from North Wales, 

 and has many characters in common with the vitreous Cop- 

 per Ores found in Cornwall : it is, however, more brittle, 

 and differs in its crystallization. This Ore varies in its con- 

 tents, the specimens from Cornwall having only Copper, 

 Iron, and Sulphury while the foreign ones sometimes con- 

 tain Silver, Arsenic, and Antimony. Its neat and smooth 

 grey steel-like appearance makes it tolerably distinct. It is 

 more shining than the usual vitreous Ore in the fracture, 

 which is mostly small, conchoidal, and bluntish. 



The present specimen has but little variation in external 

 colour, and, though easily scraped with a knife, is rather 

 harder than the common vitreous Copper. 



