Stibnite (Reflected Light)

Stibnite (Sb2S3) optical properties using a reflected-light polarizing microscope (adapted from Spry & Gedlinske, 1987):

System: Orthorhombic

Reflectance: Strong

Colour: White to greyish white

VHN and polishing hardness: 42 - 153 / soft

Pleochroism: Strong, dull grey-white, brownish grey, white

Anisotropism: Strong, but often undulose extinction- blue, grey, brown, pinkish brown

Internal reflections: Not present

Twinning: Pressure twins, deformation twins common

Commonly associated minerals: Ag minerals, antimony, berthierite, chalcopyrite, cinnabar, gold, orpiment, pyrite, pyrrhotite, realgar, sphalerite

Sample from the EOSC424 reflected light sample collection at UBC