It is also an unimportant ore of copper. Fine crystal clusters, nodular specimens, and interesting and beautiful combinations with malachite are important pieces in anyone's mineral collection. Color is azure, deep blue or pale blue if found in small crystals or crusts. Luster is vitreous to dull depending on habit. Also, aggregate crusts and radiating, botryoidal, nodular and earthy masses.
Cleavage is good in one direction and fair in another.
Fracture is conchoidal and brittle. Streak is blue. Associated Minerals are limonite , chalcopyrite , native copper , calcite , cuprite , chrysocolla , malachite and other oxidized copper minerals. Best Field Indicators are color, softness, crystal habits and associations.