Copper* 365 



SPECIES VI. 





Mineralized by Sulphur, 'with a large Propor- 

 tion of Iron. 



Telloiv Copper Ore, yellow Pyrites. 



24. Its colour is yellow, or yellow mixed 

 with red or green, or variegated like a pi- 

 geon's neck ; it is moderately hard, not rea- 

 dily giving fire with fteel as other pyrites do ; 

 in its fra&ure it prefents lharp fragments ; it 

 is fometimes found cryftalized, and fome- 

 times amorphous ; its fpecific gravity is about 

 4, i 6 ; it occurs both in feparate mafles and 

 imbodied in ftones, and is the commoneft of 

 all the copper ores. 



25. With refpect to its contents, the cryf- 

 talized fort is the pooreft in copper, of which 

 it contains only from 4 to 8 per cent, the re- 

 mainder is chiefly iron \ it is generally reddifh, 

 and is in facT: a martial pyrites, with a fmall 

 proportion of copper ; the greenifh yellow con- 

 tains moft fulphur, and from 1 5 to 20 per 

 cent, of copper ; the pure yellow contains 

 moft copper ; namely, from 20 to 30 per cent, 

 its texture is foliated ; thefe pyritous ores al- 

 ways contain argill, and a little of filiceous 

 earth. 



SPECIES VIL 



