ORES OF COPPER. 133 
mines of Michigan and the Western States; also at some 
mines north of Lake Huron ; in the San Juan mining region, 
Colorado; north of Gila Riva, near the borders of New 
Mexico and Arizona; at the Bruce Mines, Lake Huron, 
and at Prince’s Mine, Spar Island, and on Michipicoton 
Islands, Lake Superior. 
Covellite, or Blue Copper. A dull blue-black massive mineral, with 
the composition CuS. G=8°'8. it contains 66:5 per cent. of copper. 
Harrisite. A copper glance with cubic cleavage, from Canton Mine, 
Ga.; probably a pseudomorph after galenite. 
Chalcopyrite.— Copper Pyrites. peter Ton Sulphide. 
Dimetric. Crystals tetrahedral or 
octahedral ; sometimes compound. 
I I=109° 53’, and 108° 40’. Cleav- 
age indistinct. Also massive, and of 
various imitative shapes. 
Color brass-yellow, often tarnished 
deep yellow, and also iridescent. 
Streak unmetallic, greenish black, and 
but little shming. H.=3°5-4. G. 
= 4:15 -4:°3, 
Composition. CuFe 8, = Sulphur 
34°9, copper 34°6, iron 30°5=100. Fuses B.B. to a globule 
which is magnetic, owing to the iron present. Gives sulphur 
fumes on charcoal. With soda on charcoal affords a glo- 
bule of metallic iron with copper. The usual effect with 
nitric acid. 
Diff. This ore resembles native gold, and also pyrite. It 
is distinguished from gold by crumbling when it is attempted 
to cut it, mstead of separating in slices ; and from pyrite in 
its deeper yellow color, and in yielding easily to the point of 
a knife, instead of striking fire with a steel. 
Obs. Copper pyrites occurs in veins intersecting gneiss 
and other metamorphic rocks ; also in those connected with 
eruptive rocks ; and sometimes in cavities or veins in ordi- 
nary stratified rocks. It is usually associated with pyrite, 
and often with galenite, blende, and copper carbonates. The 
copper of Fahlun, Sweden, is obtained mostly from this ore, 
where it occurs with serpentine j in gneiss. Other mines of 
this ore are in the Hartz, near Goslar; in the Banat, Hun- 
gary, Thuringia, ete. The Cornwall ore is mostly of this 
kind. As prepared for sale at Redruth it rarely yields 12 

