Cornetite

Cornetite – Cu3(PO4)(OH)3
Class: Phosphates
Crystal System: Orthorhombic
Hardness: 4.5
Apatite
Talc (1)Diamond (10)
Softer than glass. A steel knife scratches it.
Origin: Origin: L’Etoile du Congo Mine, Lubumbashi, Haut-Katanga – Congo (drc)
Did you know?

Most secondary copper minerals turn green, so cornetite is the rebel: this rare phosphate comes in a deep sapphire blue instead.