Physical properties
Habit: rare tetrahedral disphenoidal crystals, botryoidal, striated, druse, usually zoned.
Color: brass yellow or honey yellow.
Luster: metallic.
Diaphaneity: opaque.
Streak: greenish black.
Cleavage: {011}, {111}.
Fracture: uneven, brittle.
Twinning: {112}.
Chemical: attacked by HNO3, corroded by a mixture of KOH + KMnO4.
Occurrence: veins
and disseminated in metamorphic and igneous rocks (e.g., gabbros, norites).
Others: n-type semiconductor with ΔEg = 0.01 eV–0.03 eV. Electrical resistivity
150 to 9000 μΩ.cm., melting point 950°C.
