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Vanadinite

From Wikipedia

Vanadinite is a mineral belonging to the apatite group of phosphates, with the chemical formula Pb5(VO4)3 Cl. It is one of the main industrial ores of the metal vanadium and a minor source of lead. A dense, brittle mineral, it is usually found in the form of red hexagonal crystals. It is formed by the oxidation of lead ore deposits such as galena. First discovered in 1801 in Mexico, vanadinite deposits have since been unearthed in South America, Europe, Africa, and other parts of North America.

Vanadinite is an uncommon mineral, only occurring as the result of chemical alterations to a preexisting material. It is therefore known as a secondary mineral. It is found in arid climates and forms by oxidation of primary lead minerals. Vanadinite is especially found in association with the lead sulfide, galena.

It was originally discovered in Mexico by the Spanish mineralogist Andrés Manuel del Río in 1801. He called the mineral "brown lead" and asserted that it contained a new element, which he first named pancromium and later, erythronium. In 1830, Nils Gabriel Sefström discovered a new element, which he named vanadium. Del Río's "brown lead" was also rediscovered, in 1838 in Zimapan, Hidalgo, Mexico, and was named vanadinite due its high vanadium content.

Deposits of vanadinite are now found worldwide.

Crystals of vanadinite conform to a hexagonal system of symmetry. This internal structure is often reflected in the hexagonal external shape of the crystals. The crystals are usually in the form of short hexagonal prisms, but can also be found as hexagonal pyramids, rounded masses or crusts.

Vanadinite is usually bright-red or orange-red in color, although sometimes brown, red-brown, gray, yellow, or colorless. Its distinctive color makes it popular among mineral collectors. Its streak can be either pale yellow or brownish-yellow.

Its hardness is 3-4 on the Mohs scale, about the same as a copper coin. Vanadinite is particularly heavy for a translucent mineral with a molecular weight approximately seven times that of water.