Sulfosalts

name colour lustre Mohs hardness specific gravity

argyrodite bluish to purplish black; steel gray when fresh metallic 2½ 6.1–6.3

bournonite steel gray to iron black metallic 2½–3 5.8–5.9

enargite gray black to iron black metallic 3 4.4–4.5

polybasite iron black metallic 2–3 6.0–6.2

proustite scarlet vermillion adamantine 2–2½ 5.6

pyrargyrite deep red adamantine 2½ 5.8

stephanite iron black metallic 2–2½ 6.2–6.3

tetrahedrite flint gray to iron or dull black metallic 3–4½ 4.6–5.1

name habit fracture or cleavage refractive indices or polished section data crystal system

argyrodite crystals and crystal aggregates; crusts; compact masses conchoidal to uneven fracture violet gray white; isotropic (canfieldite) or weakly pleochroic (argyrodite) isometric

bournonite prismatic to tabular crystals; crystal aggregates; granular to compact masses subconchoidal to uneven fracture white; weakly anisotropic and very weakly pleochroic orthorhombic

enargite tabular crystals; granular masses one perfect cleavage gray to light rose brown; strongly anisotropic; weakly pleochroic orthorhombic

polybasite tabular crystals; massive uneven fracture gray white; moderately anisotropic; weakly pleochroic monoclinic

proustite prismatic crystals; compact masses one distinct cleavage omega = 2.979–3.088

epsilon = 2.711–2.792 hexagonal

pyrargyrite prismatic crystals; compact masses one distinct cleavage omega = 3.084

epsilon = 2.881 hexagonal

stephanite prismatic to tabular crystals; disseminated grains; compact masses subconchoidal to uneven fracture strongly anisotropic orthorhombic

tetrahedrite tetrahedral crystals; granular to compact masses subconchoidal to uneven fracture gray to olive brown; isotropic isometric