Yellow Botryoidal Mimetite Crystals

Mimetite
Lead Arsenate Chloride, Pb5(AsO4)3Cl
Crystal System: Hexagonal
Hardness: 3.5
Density: 7.1

Mimetite is a rare secondary mineral found in the oxidized portions of lead deposits. It is typically associated with cerusite, plattnerite, wulfenite, smithsonite, hemimorphite, anglesite, limonite and other oxide zone minerals. Structurally, mimetite is a member of the apatite group; an end-member of the pyromorphite-mimetite series. It's given as belonging to the monoclinic crystal system in some references.

It occurs as colorless to yellow-brown or orange hexagonal, prismatic crystals which sometimes exhibit curved faces, and also occurs as rounded, globular forms. Mimetite is often difficult to distiguish from pyromorphite, and in fact it's name comes from a Greek word meaning "imitator."

Stuart provides the following remarks:

"I can only think of two minerals that come in this brilliant lemon yellow color; Sulfur and Mimetite from Mexico. These are always botryoidal with almost 'mushroom' like shapes."


Rocks from Stuart Wilensky's Collection

Index of Specimen Images

Table of Contents

bkeller@rockhounds.com 7/24/95