Cuprite Octahedron

Mineral(s): Cuprite
Locality: Rubtsovskiy Mine, Altaiskiy Krai, Western-Siberian Region, Russia

This appears to be a single 1.8 cm octahedral cuprite crystal, but it's actually three crystals closely twinned together - notice the top and center terminations! The crystals are a deep red color, but oxidation through air and light has since tarnished their surfaces to be reflectively metallic. This is to be expected, as cuprite's chemical composition is copper oxide, and many oxide minerals will react/oxidize under air, moisture and/or light.

The Rubtsovskiy Mine is a relatively newer locality that has produced cuprite crystals of incredible quality and size (much larger than this piece!).

This is also a somewhat older photo I took where I did not have enough lighting to adequately display this specimen. As a result of light balancing on Photoshop, the background appears excessively grey. It also doesn't help that the crystals are really reflective, which makes color correction and image editing more difficult.