Sulfides: Chalcopyrite

Composition: CuFeS₂; minor selenium may substitute for sulfur

Crystal system: Tetragonal; typically massive

7.4.1
chalcopyrite ore
Mt Isa mine Qld Australia

Properties:

• Metallic lustre
• Greenish yellow color, often with irridescent tarnish
• Greenish black streak
• Knife scratches easily (Mohs Hardness 3.5-4)
• High density
• Cleavage sometimes apparent
• Uneven fracture
• Not ferromagnetic
• Does not react with hydrochloric acid (HCl)

Occurrence:

Chalcopyrite, the most common copper mineral, occurs with other sulfides in hydrothermal vein, replacement and massive sulfide ore deposits and with pyrrhotite and pentlandite in massive segregations in mafic igneous rocks.

7.4.2
chalcopyrite-jasper breccia
Mt Chalmers mine Qld Australia

Chalcopyrite is the most important source of copper, although bornite, chalcocite and other copper sulfides are locally important.