Chalcopyrite

Physical Properties
Chemical formula CuFeS2
Class Sulfide
Crystal system Tetragonal
Habit Pseudotetrahedral
Massive aggregates
Prismatic
Color Brass-yellow
Sometimes tarnished
If oxidized, may show subtle
reds, greens, blues,
and purples
Hardness 3.5 to 4
Specific gravity 4.2
Cleavage Poor {011}
Fracture Uneven
Luster Metallic
Transparency Opaque
Streak Greenish black
Twinning Polysynthetic
Penetration
after Perkins, 356

Chalcopyrite in Hand Sample

Chalcopyrite hand sample

Chalcopyrite in Conococheague Fm. limestone

Further Reading

Chalcopyrite at webmineral.com

Chalcopyrite at mindat.org