Cooperite, (Pt,Pd,Ni)S, optical properties using a reflected-light polarizing microscope (adapted from Spry & Gedlinske, 1987):

System: Tetragonal

Reflectance: Medium

Colour: Brownish white

VHN and polishing hardness: 505 - 588 / medium

Pleochroism: Weak

Anisotropism: Weak to isotropic; grey-pink to grey-green, relatively strong in oil

Internal reflections: Not present

Twinning: Not present

Commonly associated minerals: Braggite, platinum, sperrylite, and other platinum minerals

Sample from the EOSC424 reflected light sample collection at UBC