Cuprite is an oxide mineral composed of copper(I) oxide Cu₂O, and is a minor ore of copper.

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. In spite of its nice color it is rarely used for jewelry because of its low Mohs hardness of 3.5 to 4. It has a relatively high specific gravity of 6.1, imperfect cleavage and a brittle to conchoidal fracture. The luster is sub-metallic to brilliant adamantine. The "chalcotrichite" variety typically shows greatly elongated (parallel to [001]) capillary or needle like crystals forms.