Smithsonite
Image: Didier Descouens (CC BY-SA 4.0)
Mineral NameSmithsonite
Chemical FormulaZnCO3
Mohs Hardness4.5
Crystal Systemtrigonal
Lustervitreous
Streak Colorwhite
Cleavageperfect rhombohedral
Fractureuneven
Specific Gravity4.4
Colorsyellowish-brown, orange-brown
Transparencytranslucent
Type LocalityGraphic Mine (Graphic shaft; Waldo-Graphic mine), Magdalena District, Socorro Co., New Mexico, USA
Mineral GroupCarbonates
Useszinc ore, collector, gemstone
Associated Mineralshemimorphite, cerussite, limonite, malachite
Rarityuncommon
Description
This specimen features botryoidal (grape-like) aggregates of yellowish-brown to orange-brown smithsonite crystals coating a dark, iron-rich matrix.
Geological Context
Smithsonite is a secondary mineral found in the oxidized zones of zinc-bearing ore deposits, typically forming from the alteration of primary zinc sulfides like sphalerite in carbonate host rocks.
