Colorless prismatic crystals of hemimorphite on matrix (4.5 × 4.0 × 2.0 cm) with calcite. Found from Ojuela mine, Mapimí, Durango, Mexico. — Photo: Ivar Leidus · CC BY-SA 4.0
Hemimorphite
Also known as: Calamine, Electric calamine.
A hydrated zinc silicate — half of the historic 'calamine' ore pair with smithsonite — mined from the oxidized tops of zinc deposits.
Intro adapted from Wikipedia (CC BY-SA).
Hemimorphite is an IMA-recognized mineral species in the silicate class, with the chemical formula Zn₄(Si₂O₇)(OH)₂·H₂O.
It crystallizes in the orthorhombic crystal system (space group Imm2).
Key properties: Mohs hardness 4.5–5; specific gravity 3.475; typically white or colorless or blue or green or yellow or brown; White streak; Vitreous, subpearly, adamantine, rarely silky luster; refractive index 1.622; optically biaxial.
IMA symbol Hmp, IMA status: approved, named in 1853.
A secondary mineral typically found in the oxidized zone of zinc-bearing mineral deposits.
It is found associated with Smithsonite, sphalerite, galena, cerussite, anglesite, calcite, aurichalcite, rosasite, hydrozincite, chrysocolla.
In allusion to the mineral's hemimorphic morphology.
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