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EntityQ420958· pop 18· linked from 14 articles

Alunogen (from French alun, "alum"), also called feather alum and hair salt is a colourless to white (although often coloured by impurities, such as iron substituting for aluminium) fibrous to needle-like aluminium sulfate mineral. It has the chemical formula Al2(SO4)3·17H2O.

Key facts

Mineral.name
Alunogen
Mineral.image
Alunogen - Almyras, Agia Varvara, Cyprus.jpg
Mineral.caption
Alunogen
Mineral.category
Sulfate minerals
Mineral.formula
Al2(SO4)3·17H2O
Mineral.IMAsymbol
Alg
Mineral.strunz
7.CB.45
Mineral.system
Triclinic
Mineral.class
Pinacoidal () (same H-M symbol)
Mineral.symmetry
P
Mineral.unit cell
a = 7.42, b = 26.97 c = 6.062 [Å]; α = 89.95° β = 97.566°, γ = 91.888°; Z = 2
Mineral.colour
Colourless; white, pale yellow to red from impurities
Mineral.habit
Platy to prismatic crystals rare, fibrous masses, crusts, and efflorescences
Mineral.twinning
On
Mineral.cleavage
Perfect on , probable on and
Mineral.fracture
Subconchoidal
Mineral.mohs
1.5–2
Mineral.lustre
Vitreous to silky

via Wikipedia infobox

Wikidata facts

Image
Alunogen - Almyras, Agia Varvara, Cyprus.jpg
Show 6 more facts
Strunz 8th edition (series ID, updated)
VI/C.04
Nickel-Strunz '10th ed', review of (9th ed/ 2009 update)
7.CB.45
IMA Mineral Symbol
Alg
chemical formula
Al₂(SO₄)₃(H₂O)₁₂·5H₂O
Nickel-Strunz 9th edition (updated 2009)
7.CB.45
Commons category
Alunogen
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Alunogen (from French alun, "alum"), also called feather alum and hair salt is a colourless to white (although often coloured by impurities, such as iron substituting for aluminium) fibrous to needle-like aluminium sulfate mineral. It has the chemical formula Al2(SO4)3·17H2O.

It is often found on the walls of mines and quarries as a secondary mineral. It can be found in the oxidation zones of some ore deposits as well as on burning coal dumps (i.e., as the product of millosevichite hydration). It also forms as a low temperature deposit in fumaroles. It occurs associated with pyrite, marcasite, halotrichite, pickeringite, epsomite, potash alum, melanterite and gypsum.

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