134 DESCRIPTIONS OF MINERALS. 



per cent., and generally only 7 or 8. and occasionally as little 

 as 3 to 4 per cent, of metal*; "6J per cent, of metal may be 

 considered an average of the produce of the total quantity of 

 ore sold."' (Phillips, 1874.) Such poverty of ore is only made 

 up by its facility of transport, the moderate expense of fuel, 

 or the convenience of smelting. Its richness may generally 

 be judged of from the color : if of a fine yellow hue, and 

 yielding readily to the hammer, it is a good ore ; but if hard 

 and pale yellow it contains much pyrite, and is of poor 

 quality. 



In the United States there are many localities of this ore. 

 It occurs in mines in Vermont, at Strafford ; and at Shrews- 

 bury, Corinth, \Yaterbury ; also in New Hampshire, Maine, 

 Massachusetts, and Connecticut; in Xew York, at the Ancram 

 lead mine : also near Rossie, and at AYurtzboro* ; in Penn- 

 sylvania, at Morgantown ; in Virginia, at the Phenix copper 

 mines, Fauquier County, and at the Walton gold mine, 

 Luzerne County; in Maryland, in the vicinity of Liberty and 

 Xew London in Frederick County ; and at the Patapsco 

 mines near Sykesville ; in North Carolina, in Davidson and 

 Guilford counties. In Michigan, where native copper is so 

 abundant, this is a rare ore ; but it occurs at Presqifisle, at 

 Mineral Point, and in "Wisconsin, where it is the predomi- 

 nating ore : in Tennessee, in Polk County, at the Hiwassee 

 mines ; in the San Juan mining region, Colorado ; in Lan- 

 der Co., and elsewhere, Xevada ; at Copperopolis, Calaveras 

 Co., California ; also at the Bruce and other mines on Lake 

 Huron ; and Michipicoton Islands, in Lake Superior. 



Culjanite is a copper-and-iron sulphide, containing Sulphur 39 "0, 

 iron 38-0, copper 19-8, silica 2 -3=99 12. 



Bornite. — Erubescite. Variegated Copper Pyrites. 



Isometric. Cleavage octahedral in traces. Occurs in oc- 

 tahedrons and dodecahedrons. Also massive. 



Color between copper-red and pinchbeck-brown. Tar- 

 nishes rapidly on exposure. Streak pale grayish-black and 

 but slightly shining. Brittle. H. = 3. G.='o. 



Composition. Cu.Fe S 3 = Sulphur 23-6, copper 55 -58, iron 

 16*36 ; but varies much. 



The ore of Bristol, Conn., afforded Sulphur 25-83, copper 

 61*79, ironll-rr=r99-o9. 



B. B. on charcoal fuses to a brittle o-lobule attractable bv 



