Copper(II) oxide, typically black and often earthy (Melaconite). It's a grounding and energizing stone, enhancing vitality and courage.
Steel-Grey to Black, often earthy or forms minute scales/lath-like crystals
Tenorite is classified as a oxide mineral mineral which typically crystallizes in the monoclinic system. Its chemical formula is CuO. Common crystal habits include lathlike crystals, curved, scaly, dendritic; commonly pulverulent, earthy, massive.