CHEMISTRY - Sb2S3
CRYSTALLOGRAPHY - Orthorhombic
CRYSTAL GROWTH AND HABITS - Stibnite commonly forms elongated prisms striated parallel to the long axis and has complex terminations. Bent and or twisted crystals are not uncommon. Stibnite also grows in sprays of complex acicular groups. It can also be granular to massive.
COLOR AND OPTICAL PROPERTIES - Steel gray to silver in color, opaque.
HARDNESS - 2
SPECIFIC GRAVITY - 4.63
LUSTER - Bright metallic
STREAK - Lead gray
BREAKABILITY - Very good cleavage on {010} poor along {100} and {110}; subconchoidal fracture; flexible and somewhat sectile.
OCCURRENCE - Found in high to low temperature hydrothermal veins.
ASSOCIATED MINERALS - Realgar, Orpiment, Cinnabar, Galena, Pyrite, Marcasite, Arsenopyrite, Calcite, Barite and Quartz
MINERAL NAME - From the Greek stibi or the Latin stibium name for the mineral.