Cobaltoan Smithsonite
Image: <a href="//commons.wikimedia.org/wiki/User:Archaeodontosaurus" title="User:Archaeodontosaurus">Didier Descouens</a> (CC BY-SA 4.0)
Mineral NameCobaltoan Smithsonite
Chemical Formula(Zn,Co)CO3
Mohs Hardness4
Crystal Systemtrigonal
Streak Colorwhite
Cleavageperfect rhombohedral {1011}
Fractureuneven to subconchoidal
Specific Gravity4.3
Colorspink, lavender, purple
Transparencytranslucent
Type LocalityTsumeb Mine (Tsumcorp Mine), Tsumeb, Otjikoto (Oshikoto) Region, Namibia
Mineral GroupCarbonates
Usescollector's item, minor ore of zinc
Associated Mineralsmalachite, azurite, cerussite, hemimorphite
Rarityuncommon
Description
This specimen features a beautiful botryoidal aggregate of small, lustrous, pink to lavender-purple cobaltoan smithsonite crystals, forming a vibrant crust over a darker matrix.
Geological Context
Cobaltoan smithsonite is a secondary mineral that forms in the oxidized zones of zinc-rich ore deposits, often in carbonate host rocks, where cobalt is also present.
