Hemimorphite
Image: Photo by and (c)2015 Derek Ramsey (Ram-Man) (CC BY-SA 4.0)
Mineral NameHemimorphite
Chemical FormulaZn₄(Si₂O₇)(OH)₂·H₂O
Mohs Hardness4.5
Crystal Systemorthorhombic
Lustervitreous
Streak Colorwhite
Cleavageperfect on {110}
Fractureconchoidal
Specific Gravity3.4
Colorslight blue, greenish-blue, white, yellowish-brown
Transparencytransparent
Type LocalitySanta Eulalia, Chihuahua, Mexico
Mineral GroupSilicates
Usesore of zinc, collector, gemstone
Associated Mineralssmithsonite, sphalerite, cerussite, limonite
Rarityuncommon
Description
This specimen displays beautiful botryoidal formations of light blue to greenish-blue hemimorphite, with some areas exhibiting a lighter, almost off-white or yellowish-brown coloration, possibly from the host rock or other minerals.
Geological Context
Hemimorphite is a secondary mineral typically found in the oxidized zones of zinc-lead ore deposits, forming through the alteration of primary zinc sulfides like sphalerite in the presence of silica-rich waters.
