Vanadinite

Formula: Pb₅(VO₄)₃Cl

Colour: Orange-red, red-brown, brown, bright red, yellow, whitish; pale straw-yellow; colourless or weakly tinted in transmitted light.

Lustre: Sub-Adamantine, Resinous

Hardness: 2½ – 3

Specific Gravity: 6.88

Crystal System: Hexagonal

Member of: Apatite Group > Apatite Supergroup

Name: The name reflects its vanadium content.

Type Locality: Zimapán, Zimapán Municipality, Hidalgo – Mexico

Isostructural with: Mimetite, Pyromorphite

Apatite Group. Apatite Supergroup. The vanadate analogue of Mimetite and Pyromorphite. Forms a solid solution series toward Mimetite (Mimetite-Vanadinite Series), and a series with Pyromorphite. There is a complete series between mimetite, pyromorphite and vanadinite. Vanadinite is a secondary lead chlorovanadate. It is chemically related to otherwise much more structurally complex but chemically similar to erikjonssonite, hereroite, janchevite, and kombatite. It is almost always found in the oxidation zone of lead deposits in arid climates resulting from the alteration of vanadiferous sulphides and silicates of the gangue and wall rocks. First discovered by Señor A.M. del Rio (1764-1849), Professor, School of Mines of Mexico, Zimapan, before the element vanadium was discovered in 1830.