Descloizite

Introduction: Descloizite is named after a former professor of mineralogy at the University of Paris, Alfred Legrand Des Cloizeaus. They form striking dark orange-red to brown to black crystals in a variety of wonderful shapes and sizes. An important ore of vanadium, it is used in the production of steel alloy catalysts, ceramic pigments, as a drying agent in ink and paint and in blue and yellow paint.

Distribution: The Otavi Mountains holds the distinction of where the world's largest concentration of descloizite where found, mainly in the Berg Aukas and Abenab Mines. These specimens are displayed in collections the world over, the most common being spear-shaped, dark-brown crystals. It also occurs 20km north of Opuwo in Kaokoland together with galena in dolomite.

Composition: Vanadate

Crystal system: Orthorhombic

Lustre: Lustrous, greasy

Streak: Orange, brown-red

Hardness: 3-3.5