Millosevichite

{{Short description|Rare sulfate mineral}}

{{infobox mineral

| name = Millosevichite

| image = Millosevichite-629135.jpg

| alt =

| caption = Porous yellow millosevichite. Dimensions: 14 mm × 10 mm × 8 mm. Locality: Kladno Mine (Nejedlý I Mine; Zdeněk Nejedlý Mine; Schoeller Mine; Schöller Mine), Libušin, Kladno, Central Bohemia Region, Bohemia (Böhmen; Boehmen), Czech Republic.

| category = Sulfate mineral

| formula = Al₂(SO₄)₃

| IMAsymbol = Msv{{Cite journal|last=Warr|first=L.N.|date=2021|title=IMA–CNMNC approved mineral symbols|url=https://www.cambridge.org/core/journals/mineralogical-magazine/article/imacnmnc-approved-mineral-symbols/62311F45ED37831D78603C6E6B25EE0A|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}}

| strunz = 7.AB.05

| dana =

| system = Trigonal

| class = Rhombohedral ({{overline|3}})
H-M symbol: ({{overline|3}})

| symmetry = R{{overline|3}}

| unit cell = a = 8.05 Å, c = 21.19 Å; Z = 6

| color = Indigo, bright red, brick-red

| habit = Granular aggregates of minute crystals; stalactitic porous masses

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| mohs = 1.5

| luster = Vitreous

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| diaphaneity = Semitransparent

| gravity = 1.72 measured

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| opticalprop = Uniaxial (+)

| refractive = n_ω = 1.500 n_ε = 1.515

| birefringence = δ = 0.015

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| other = Hygroscopic

| references = [http://www.handbookofmineralogy.org Handbook of Mineralogy][http://www.mindat.org/min-2713.html Mindat][http://webmineral.com/data/Millosevichite.shtml Webmineral]

}}

Millosevichite is a rare sulfate mineral with the chemical formula Al₂(SO₄)₃. Aluminium is often substituted by iron. It forms finely crystalline and often porous masses.

It was first described in 1913 for an occurrence in Grotta dell'Allume, Porto Levante, Vulcano Island, Lipari, Aeolian Islands, Sicily. It was named for Italian mineralogist Federico Millosevich (1875–1942) of the University of Rome.

The mineral is mainly known from burning coal dumps, acting as one of the main minerals forming sulfate crust. It can be also found in volcanic fumeroles (solfatara environments).Chesnokov B. V. and Shcherbakova E. P. 1991: Mineralogiya gorelykh otvalov Chelyabinskogo ugolnogo basseina – opyt mineralogii tekhnogenesa. Nauka, Moscow

It occurs with native sulfur, sal ammoniac, letovicite, alunogen and boussingaultite.