Hubnerite: Gemstone Information

Hübnerite is Mn2WO4 and is found as transparent to translucent prismatic monoclinic yellowish brown to reddish brown crystals with striations in the direction of elongation, with one direction of perfect cleav-age and a hardness of 4–4.5, varying with direction. The SG is 7.12–7.18 and the RI for the alpha, beta and gamma rays is 2.17–2.20, 2.22 and 2.30–2.32,biaxial positive with birefringence 0.13. Deep blood-red internal reflections are attractive, combined with the metallic-adamantine-resinous lustre.