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Chemical composition FeS2
Crystal system Cubic
Habit Cubic, faces may be striated, but also frequently octahedral and pyritohedron. Often inter-grown, massive, radiated, granular, globular and stalactitic.
Cleavage Indistinct on {001}; partings on {011} and {111}
Fracture Very uneven, sometimes conchoidal
Hardness 6–6.5
Refractive index a = 1.730; b = 1.758; y = 1.838
Specific gravity 4.8-4.9
Lustre Metallic