Libethenite

Libethenite is a rare mineral from the phosphate group, composed of hydrated copper phosphate (Cu₂PO₄OH). It is characterized by its prismatic or globular crystals with olive-green, dark green to blackish-green colors, sometimes with a vitreous luster.

It forms in the oxidation zones of copper deposits, often associated with malachite, azurite, chrysocolla, or cuprite. Fine specimens, particularly those from the Democratic Republic of Congo, Portugal, Chile, and the United States, are prized by collectors for their rarity and well-formed crystals.