From Surf Wiki (app.surf) — the open knowledge base

Alunogen

Aluminium sulfate mineral

Summary

Aluminium sulfate mineral

Field	Value
name	Alunogen
image	Alunogen - Almyras, Agia Varvara, Cyprus.jpg
caption	Alunogen
category	Sulfate minerals
formula	Al2(SO4)3·17H2O
IMAsymbol	Alg
strunz	7.CB.45
system	Triclinic
class	Pinacoidal ()
(same H-M symbol)
symmetry	P
unit cell	a = 7.42, b = 26.97
c = 6.062 [Å]; α = 89.95°
β = 97.566°, γ = 91.888°; Z = 2
colour	Colourless; white, pale yellow to red from impurities
habit	Platy to prismatic crystals rare, fibrous masses, crusts, and efflorescences
twinning	On
cleavage	Perfect on , probable on and
fracture	Subconchoidal
mohs	1.5–2
lustre	Vitreous to silky
diaphaneity	Transparent
gravity	1.72–1.77
opticalprop	Biaxial (+)
refractive	nα = 1.473 nβ = 1.474 nγ = 1.480
birefringence	δ = 0.007
2V	Measured: 31 to 69°
references

(same H-M symbol) c = 6.062 [Å]; α = 89.95° β = 97.566°, γ = 91.888°; Z = 2 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.

The crystallochemical formula, can be written as: [Al(H2O)6]2(SO4)3.5H2O. The second formula shows that H2O in the alunogen formula occurs both as ligand (coordinative form) and loosely bound (crystallization) form.

References

Warr, L.N.. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine.
[http://rruff.info/doclib/hom/alunogen.pdf Handbook of Mineralogy]
[http://www.mindat.org/min-162.html Mindat]
[http://webmineral.com/data/Alunogen.shtml Webmineral]
"Alunogen R070601".
"Alunogen R060015".

Wikipedia Source

This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page.

sulfate-minerals aluminium-minerals triclinic-minerals minerals-in-space-group-2

Want to explore this topic further?

Ask Mako anything about Alunogen — get instant answers, deeper analysis, and related topics.

Research with Mako

Free with your Surf account

Content sourced from Wikipedia, available under CC BY-SA 4.0.

This content may have been generated or modified by AI. CloudSurf Software LLC is not responsible for the accuracy, completeness, or reliability of AI-generated content. Always verify important information from primary sources.

Report