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Silicate mineral
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Hemimorphite
General
Category
Sorosilicates
Formula (repeating unit)
Zn4Si2O7(OH)2·H2O
IMA symbol
Hmp[1]
Strunz classification
9.BD.10
Crystal system
Orthorhombic
Crystal class
Pyramidal (mm2) H-M symbol: (mm2)
Space group
Imm2
Unit cell
a = 8.367(5), b = 10.73 c = 5.155(3) [Å]; Z = 2
Identification
Color
White, grey
Crystal habit
Polar crystals, with different or hemimorphic ends. Also coxcomb masses, mammillary, stalactitic, or massive
Twinning
Rare on {001}
Cleavage
Perfect on {110}, poor on {101}, {001} rare
Fracture
Uneven to conchoidal
Tenacity
Brittle
Mohs scale hardness
4.5–5
Luster
Vitreous, adamantine, rarely silky
Streak
White
Diaphaneity
Transparent to translucent
Specific gravity
3.516–3.525
Optical properties
Biaxial (+)
Refractive index
nα = 1.614 nβ = 1.617 nγ = 1.636
Birefringence
δ = 0.022
2V angle
Measured: 46°, calculated: 44°
Solubility
Soluble in acid
References
[2][3][4]
Hemimorphite is the chemical compound Zn4(Si2O7)(OH)2·H2O, a component of mineral calamine. It is a silicate mineral which, together with smithsonite (ZnCO3), has been historically mined from the upper parts of zinc and lead ores. Both compounds were originally believed to be the same mineral and classified as calamine. In the second half of the 18th century, it was discovered that these two different compounds were both present in calamine. They closely resemble one another.
The silicate was the rarer of the two and was named hemimorphite because of the hemimorph development of its crystals. This unusual form, which is typical of only a few minerals, means that the crystals are terminated by dissimilar faces. Hemimorphite most commonly forms crystalline crusts and layers, also massive, granular, rounded and reniform aggregates, concentrically striated, or finely needle-shaped, fibrous or stalactitic, and rarely fan-shaped clusters of crystals.
Some specimens show strong green fluorescence in shortwave ultraviolet light (253.7 nm) and weak light pink fluorescence in longwave UV.
Hemimorphite is the chemical compound Zn4(Si2O7)(OH)2·H2O, a component of mineral calamine. It is a silicate mineral which, together with smithsonite (ZnCO3)...
zinc carbonate (ZnCO3). Historically, smithsonite was identified with hemimorphite before it was realized that they were two different minerals. The two...
and as post mine incrustations. It occurs associated with smithsonite, hemimorphite, willemite, cerussite, aurichalcite, calcite and limonite. It was first...
hydrothermal mineral deposits. It occurs in association with smithsonite, hemimorphite, scorodite, olivenite, calcite, quartz and iron and manganese oxides...
Zinc silicate may refer to: Hemimorphite, a zinc sorosilicate Willemite, a zinc neosilicate Sauconite, a zinc phyllosilicate This set index article lists...
and zinc deposits. Associated minerals include: rosasite, smithsonite, hemimorphite, hydrozincite, malachite and azurite. It was first described in 1839...
chrysocolla (especially when impregnating quartz); lazulite; smithsonite; hemimorphite; wardite; and a fossil bone or tooth called odontolite or "bone turquoise"...
Other source minerals for zinc include smithsonite (zinc carbonate), hemimorphite (zinc silicate), wurtzite (another zinc sulfide), and sometimes hydrozincite...
brochantite, anglesite, caledonite, leadhillite, cerussite, malachite and hemimorphite. A shallow pocket of crystals of an intense cobalt blue, from Darwin...
hydrothermal lead deposits. It occurs with cerussite, anglesite, smithsonite, hemimorphite, vanadinite, pyromorphite, mimetite, descloizite, plattnerite and various...
association with lead and arsenic minerals, including pyromorphite, cerussite, hemimorphite, smithsonite, vanadinite, anglesite, pyrite, mottramite, willemite, and...
/parasymplesite, and paradamite, as well as specimens of scorodite, hemimorphite, plattnerite, aurichalcite, rosasite, fluorite, calcite, wulfenite, mimetite...
also found in marble and may be the result of a metamorphism of earlier hemimorphite or smithsonite. Crystals have the form of hexagonal prisms terminated...
malachite, azurite, brochantite, chrysocolla, cervantite, stibiconite, hemimorphite and calcite in the type locality; and with spionkopite, chalcopyrite...
mixture of the virtually indistinguishable zinc ores smithsonite and hemimorphite) as the zinc component of brass. The resulting brasses, produced by heating...
oxidized zones of zinc and copper deposits. It occurs in association with hemimorphite, smithsonite, chrysocolla, coronadite and various iron oxides. It was...
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