Hemimorphite
Image: Ivar Leidus (CC BY-SA 4.0)
Mineral NameHemimorphite
Chemical FormulaZn₄(Si₂O₇)(OH)₂·H₂O
Mohs Hardness4.5
Crystal Systemorthorhombic
Lustervitreous
Streak Colorwhite
Cleavageperfect on {110}, good on {101}
Fractureconchoidal
Specific Gravity3.4
Colorscolorless, white, pale pink
Transparencytransparent
Type LocalityOjuela mine, Mapimí, Durango, Mexico
Mineral Groupsorosilicate
Usesore of zinc, collector
Associated Mineralscalcite, smithsonite, cerussite
Rarityuncommon
Description
A cluster of colorless to very pale white, prismatic hemimorphite crystals forming radiating aggregates on a dark matrix, with some smaller, blockier crystals possibly being calcite. The crystals exhibit excellent transparency and a vitreous luster.
Geological Context
Hemimorphite is a secondary mineral formed in the oxidized zone of zinc-lead ore deposits, typically resulting from the alteration of primary zinc sulfides like sphalerite. It often occurs in vugs and cavities in limestones or dolomites.
