Vanadinite

Vanadinite is formed as a secondary mineral in desert lead deposits often associated with mimetite and pyromorphite. When first found, vanadinite was recognized as a lead mineral with reference to its red or brown color, which explains why the type locality mineral for vanadium was called “plombo rojo” in Mexico.

First discovered in 1801 in Mexico, vanadinite deposits have since been unearthed in South America, Europe, Africa, and North America.

Vanadinite is in the apatite group of phosphates, and forms a chemical series with the minerals pyromorphite (Pb₅(PO₄)₃Cl) and mimetite (Pb₅(AsO₄)₃Cl), with both of which it may form solid solutions. Whereas most chemical series involve the substitution of metallic ions, this series substitutes its anion groups; phosphate (PO₄), arsenate (AsO₄) and vanadate (VO₄).

Vanadinite: Gemmy Mineral. Cluster of reddish brown tabular vanadinite from ACF mine, Mibladen, Morocco
Photo: Ivar Leidus

Vanadinite most often forms as simple hexagonal prisms of modest size as very attractive bright red to orange-red color crystals, although sometimes brown, red-brown, grey, yellow, or colourless. Its distinctive colour makes it popular among mineral collectors. Its streak can be either pale yellow or brownish-yellow. Vanadinite may be transparent, translucent or opaque, and its lustre can range from resinous to adamantine.

Vanadinite is very brittle, producing small, conchoidal fragments when fractured. Its hardness is 3–4 on the Mohs scale, about the same as a copper coin. Vanadinite is particularly heavy for a translucent mineral.

Vanadium is also present in crude oil, tar sands, and coal.

While vanadinite is described in the literature as an uncommon mineral, Morocco has made it more common in the recent years.

Vanadinite: Gemmy Mineral Killer vanadinite crystals from Morocco

Killer vanadinite crystals from Morocco
Photo: Phdminerals/Diego Savard

Class: Phosphates, arsenates, vanadates
Member of: Apatite Group
Chemical Formula: Pb₅(VO₄)₃Cl
Crystal system: Hexagonal
Color: Bright red, orange, brown, yellow-brown, yellow, greenish-brown
Mohs scale hardness: 3–4
Type Locality: Zimapán, Zimapán Municipality, Hidalgo, Mexico