Chalcopyrite

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Chalcopyrite
Image:ChalcopyriteUSGOV.jpg
General
Category	Mineral
Chemical formula	copper iron sulfide:CuFeS₂
Identification
Color	Brass yellow, may have iridescent purplish tarnish.
Crystal habit	predominantly the disphenoid and resembles a tetrahedron. Crystals sometines twinned. Also commonly massive, and sometimes botryoidal.
Crystal system	tetragonal bar 4 2m
Cleavage	[112] Indistinct
Fracture	conchoidal and brittle
Mohs Scale hardness	3.5
Luster	metallic
Refractive index	opaque
Pleochroism	N/A
Streak	dark green
Specific gravity	4.1 - 4.3
Fusibility	2
Solubility	?
Other Characteristics	magnetic on heating
Major varieties

Chalcopyrite is a copper iron sulfide mineral that crystallizes in the tetragonal system. It has the chemical composition CuFeS₂. It has a brassy to golden yellow color and a hardness of 3.5 to 4 on the Mohs scale. Due to its color and high copper content, chalcopyrite has often been referred to as "yellow copper".

Chalcopyrite is often confused with pyrite, although the latter has a cubic and not a tetragonal crystal system. Further, chalcopyrite is more often massive and less brittle. Chalcopyrite is also a darker yellow in color.

Chalcopyrite is one of the most important copper ores. Chalcopyrite ore occurs in a variety of ore types, from huge masses as at Timmins, Ontario, to irregular veins and disseminations associated with granitic to dioritic intrusives as in the porphyry copper deposits of Broken Hill, the American cordillera and the Andes.