Its rarity and attractiveness are the reason for the typically high prices one would expect to pay for a fine specimen. Color is typically brown to reddish brown to black also yellow to orange with increase in copper content. Luster is greasy. Crystals are transparent to opaque. Cleavage is none.
Fracture is conchoidal to uneven.
Hardness is 3 to 3.5. Streak is brownish red to orange to yellow. Associated Minerals are wulfenite , vanadinite , mottramite , pyromorphite , and cerussite .