Locality: Star of the Congo mine, near Lubumbashi, and at the Kalabi and Lukini mines, Katanga Province, Congo (Shaba Province, Zaire).
Name Origin: Named for Jules Cornet (1865-1929), Belgian geologist.
Cornetite is a rare secondary copper mineral that is noted for its deep blue, green-blue to green color. It is found in highly weathered, oxidation zones of copper sulfide ore bodies. It has a good deep color, nice crystal forms and an attractive sparkle, all the ingredients for a popular collection mineral.
Physical Properties of Cornetite
Color: dark blue, green-blue to green.
Transparency: Specimens are translucent.
Crystal System: orthorhombic; 2/m2/m2/m
Crystal Habits: include crystals that are short, rounded, nearly diamond-shaped prisms that are terminated by a dome with trapezohedral faces, also as tiny crystalline druzes, fibrous masses and crusts.
Specific Gravity : approximately 4.1 (above average for translucent minerals)