Mimetite
Image: Robert M. Lavinsky (CC BY-SA 3.0)
Mineral NameMimetite
Chemical FormulaPb₅(AsO₄)₃Cl
Mohs Hardness3.5
Crystal Systemhexagonal
Lusterresinous
Streak Colorwhite to yellowish-white
Cleavageimperfect on {1010}
Fractureconchoidal
Specific Gravity7.24
Colorsyellow, orange, brown, white, colorless, yellowish-green
Transparencytranslucent
Type LocalityMt Bonnie Mine, Grove Hill, Northern Territory, Australia
Mineral Grouparsenates
Usescollector, minor lead ore
Associated Mineralscerussite, anglesite, galena, pyromorphite, limonite
Rarityuncommon
Description
This specimen displays numerous yellowish-green, translucent, barrel-shaped to prismatic Mimetite crystals scattered across a dark, botryoidal to earthy matrix, likely composed of iron oxides.
Geological Context
Mimetite is a secondary mineral that forms in the oxidized zone of lead ore deposits, resulting from the alteration of primary lead minerals in the presence of arsenic-bearing solutions.
