Smithsonite
Image: Bureau of Mines (Public domain)
Mineral NameSmithsonite
Chemical FormulaZnCO₃
Mohs Hardness4
Crystal Systemtrigonal
Lustervitreous
Streak Colorwhite
Cleavageperfect rhombohedral {1011}
Fractureuneven
Specific Gravity4.35
Colorsblue, green, yellow, pink, purple, brown, white, gray
Transparencytransparent
Type LocalityKelley Mine, Socorro County, New Mexico
Mineral GroupCarbonates
Usesore of zinc, collector's specimens, minor gemstone
Associated Mineralshemimorphite, cerussite, anglesite, galena, sphalerite, calcite
Rarityuncommon
Description
This specimen displays a botryoidal (grape-like) aggregate of greenish-blue smithsonite, exhibiting a waxy to vitreous luster. The rounded, bubbly texture is characteristic of its common habit.
Geological Context
Smithsonite is a secondary mineral that forms in the oxidized zones of zinc-rich ore deposits, typically as an alteration product of primary zinc sulfides like sphalerite. It often occurs in limestone or dolomite host rocks.
