Crocoite
Image: Rock Currier (CC BY 3.0)
Mineral NameCrocoite
Chemical FormulaPbCrO4
Mohs Hardness2.5
Crystal Systemmonoclinic
Lusteradamantine
Streak Colororange-yellow
Cleavagegood on {110}, distinct on {100} and {001}
Fractureuneven
Specific Gravity5.9
Colorsorange-red, bright red, hyacinth red
Transparencytranslucent
Type LocalityCongonhas do Campo, Minas Gerais, Brazil
Mineral GroupChromates
Usescollector's mineral, minor ore of lead and chromium
Associated Mineralscerussite, pyromorphite, wulfenite, mimetite, goethite, limonite
Rarityuncommon
Description
The image displays a cluster of vibrant orange-red, slender, prismatic to acicular crocoite crystals, some forming radiating aggregates, set against a dark matrix.
Geological Context
Crocoite is a secondary mineral found in the oxidized zones of lead deposits, forming when lead-bearing minerals react with chromium-bearing solutions, often derived from the alteration of ultramafic rocks.
