Hemimorphite
Image: <a href="//commons.wikimedia.org/wiki/User:Archaeodontosaurus" title="User:Archaeodontosaurus">Didier Descouenss</a> (CC BY-SA 3.0)
Mineral NameHemimorphite
Chemical FormulaZn₄(Si₂O₇)(OH)₂·H₂O
Mohs Hardness4.5
Crystal Systemorthorhombic
Lustervitreous
Streak Colorwhite
Cleavageperfect on {110}
Fractureconchoidal to uneven
Specific Gravity3.4
Colorswhite, pale pink, brownish
Transparencytransparent to translucent
Type LocalityOjuela Mine, Mapimí, Mun. de Mapimí, Durango, Mexico
Mineral GroupSilicates
Usesore of zinc, collector
Associated Mineralslimonite, smithsonite, cerussite
Rarityuncommon
Description
This specimen displays numerous radiating clusters of bladed to tabular hemimorphite crystals, predominantly white to very pale pinkish-brown, growing on a reddish-brown iron-rich matrix.
Geological Context
Hemimorphite is a secondary mineral typically found in the oxidized zones of zinc-lead ore deposits, forming from the alteration of primary zinc minerals like sphalerite. It often occurs in karst environments.
