Perfect Cuprite Crystal

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Perfect Cuprite Crystal, From Tsumeb Mine, Tsumeb, Namibia

Cuprite
Formula: Cu₂O
System: Isometric
Colour: Dark red to cochineal ...
Lustre: Adamantine, Sub-Metallic, Earthy Hardness:3½ - 4
From Villecun, Olmet-et-Villecun, Hérault, Occitanie, France

Its dark crystals with red internal reflections are in the isometric system hexoctahedral class, appearing as cubic, octahedral, or dodecahedral forms, or in combinations. Penetration twins frequently occur.

It is a secondary mineral which forms in the oxidized zone of copper sulfide deposits. It frequently occurs in association with native copper, azurite, chrysocolla, malachite, tenorite and a variety of iron oxide minerals. It is known as ruby copper due to its distinctive red color.