Godovikovite

{{Short description|Sulfate mineral}}

{{Infobox mineral

| name = Godovikovite

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| image = Godovikovite with red demicheleite-(Cl).jpg

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| caption = White godovikovite with minor red demicheleite-(Cl) (IMA 2008-020) from La Fossa Crater, Vulcano Island, Messina Province, Sicily, Italy

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| category = Sulfates

| formula = {{Format molecular formula|(NH4)(Al,Fe+3)(SO4)2}}

| IMAsymbol = God{{Cite journal|last=Warr|first=L.N.|date=2021|title=IMA–CNMNC approved mineral symbols|journal=Mineralogical Magazine|volume=85|issue=3|pages=291–320|doi=10.1180/mgm.2021.43|bibcode=2021MinM...85..291W|s2cid=235729616|doi-access=free}}

| molweight = 244.36

| strunz = 07.AC.20(07)

| dana = 28.03.05.02

| system = Trigonal

| class = Trapezohedral

| symmetry = Trigonal enantiomorph

| unit cell = a = 4.75Å, c = 8.30(1)Å

| color =

| colour = White, colourless

| habit = Very small hexagonal blades

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| fracture = Uneven

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| mohs = 2

| luster = Earthy/dull

| streak = White

| diaphaneity = Transparent to translucent

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| density = 2.53

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| birefringence = 0.009

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| solubility = Slowly in H2O

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Godovikovite is a rare sulfate mineral with the chemical formula: (NH₄)Al(SO₄)₂. Aluminium can partially be substituted by iron. Hydration of godovikovite gives the ammonium alum, tschermigite. The mineral forms cryptocrystalline, often porous, masses, usually of white colour. Single crystals are very small hexagonal blades. Typical environment for godovikovite are burning coal sites (mainly dumps).{{Cite web|last=|first=|date=|title=Godovikovite|url=http://www.handbookofmineralogy.com/pdfs/godovikovite.pdf|archive-url=|archive-date=|access-date=15 February 2021|website=Handbook of Mineralogy}} There the mineral acts, together with millosevichite, as one of the main components of so-called sulfate crust.Chesnokov B. V. and Shcherbakova E. P. 1991: Mineralogiya gorelykh otvalov Chelyabinskogo ugolnogo basseina - opyt mineralogii tekhnogenesa. Nauka, MoscowJambor J. L. and Grew E. S. 1990: New mineral names. American Mineralogist, 76, pp. 240-246

It was first described in 1988 for an occurrence in the Chelyabinsk coal basin, Chelyabinsk Oblast, Southern Urals, Russia, and named for Russian mineralogist Aleksandrovich Godovikov (1927–1995).[http://www.mindat.org/min-1717.html Godovikovite on Mindat.org]