Vanadinite

Vanadinite from the Mibladen Mining District, Midelt Province, Morocco, measuring 90 × 68 × 55 mm and weighing 349 grams. A good-sized piece from what is, without much argument, the best Vanadinite locality in the world.

Vanadinite is lead chlorovanadate, Pb5(VO4)3Cl, and Mibladen material is prized above all other localities for the depth and brightness of its red to orange colour, usually showing as hexagonal crystals and crystal aggregates on a matrix of barite or goethite-stained rock. It forms in the oxidised zone of lead deposits, where weathering releases lead from Galena while vanadium is supplied from the surrounding sediments, the two combining as mineralising groundwater moves through the deposit. Mibladen's deposits sit within Triassic-Jurassic red beds in the Moroccan Atlas region, a setting that has made the district uniquely productive for this species since serious mining of it began in the mid-twentieth century.

Moroccan Vanadinite from Mibladen effectively defines the species for most collectors, and specimens of this size and colour saturation are what keep the locality in such high demand decades after it was first worked for lead. This piece is from the David Vince Collection.