Magnetite (Reflected Light)

Magnetite (Fe2O4) optical properties using a reflected-light polarizing microscope (adapted from Spry & Gedlinske, 1987):
System: Cubic
Reflectance: Medium
Colour: Grey, commonly with brownish tint
VHN and polishing hardness: 592 (average) / hard
Pleochroism: Nonpleochroic
Anisotropism: Isotropic
Internal reflections: Not present except when Mn rich
Twinning: (111) commonly lamellar twinning
Commonly associated minerals: Bravoite, chalcopyrite, cubanite, galena, hematite, ilmenite, marcasite, pentlandite, pyrite, pyrrhotite, rutile, sphalerite, ulvospinel, valleriite, zincite
Sample from the EOSC424 reflected light sample collection at UBC