Felsőbányaite or basaluminite is a hydrated

aluminium Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. I ...

sulfate mineral The sulfate minerals are a class of minerals that include the sulfate ion () within their structure. The sulfate minerals occur commonly in primary evaporite depositional environments, as gangue minerals in hydrothermal veins and as secondary mine ...

with formula: Al₄(SO₄)(OH)₁₀·4H₂O. It is a rare white to pale yellow mineral which typically occurs as globular masses and incrustations or as minute rhombic crystals. It crystallizes in the

monoclinic In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in the orthorhombic s ...

crystal system In crystallography, a crystal system is a set of point groups (a group of geometric symmetries with at least one fixed point). A lattice system is a set of Bravais lattices. Space groups are classified into crystal systems according to their poin ...

. It occurs as a weathering product under acidic conditions associated with

pyrite The mineral pyrite (), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Fe S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral. Pyrite's metallic luster and pale brass-yellow hue giv ...

marcasite The mineral marcasite, sometimes called “white iron pyrite”, is iron sulfide (FeS2) with orthorhombic crystal structure. It is physically and crystallographically distinct from pyrite, which is iron sulfide with cubic crystal structure. Both ...

decomposition. Associated minerals include hydrobasaluminite, hydroargillite, meta-aluminite,

allophane Allophane is an amorphous to poorly crystalline hydrous aluminium silicate clay mineraloid. Its chemical formula is Al2O3·(SiO2)1.3-2·(2.5-3)H2O. Since it has short-range atomic order, it is a mineraloid, rather than a mineral, and can be ident ...

gibbsite Gibbsite, Al(OH)3, is one of the mineral forms of aluminium hydroxide. It is often designated as γ-Al(OH)3 (but sometimes as α-Al(OH)3.). It is also sometimes called hydrargillite (or hydrargyllite). Gibbsite is an important ore of aluminiu ...

gypsum Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula . It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard or sidewalk chalk, and drywal ...

and

aragonite Aragonite is a carbonate mineral, one of the three most common naturally occurring crystal forms of calcium carbonate, (the other forms being the minerals calcite and vaterite). It is formed by biological and physical processes, including pre ...

. Felsőbányaite was first described in 1853 for an occurrence in the Baia Sprie mine,

Baia Sprie Baia Sprie (; hu, Felsőbánya, german: Mittelstadt) is a town in Maramureș County, northern Romania. Baia Sprie is situated at a distance of from Baia Mare. The town administers three villages: Chiuzbaia (''Kisbánya''), Satu Nou de Sus (''F ...

(''Felsőbánya''),

Maramureș County Maramureș County () is a county (județ) in Romania, in the Maramureș region. The county seat is Baia Mare. Name In Hungarian it is known as ''Máramaros megye'', in Ukrainian as Мараморо́щина, in German as ''Kreis Marmarosch' ...

Romania Romania ( ; ro, România ) is a country located at the crossroads of Central, Eastern, and Southeastern Europe. It borders Bulgaria to the south, Ukraine to the north, Hungary to the west, Serbia to the southwest, Moldova to the east, and ...

, and named for the locality. The mineral name ''basaluminite'' was used for an occurrence of the same mineral in England in 1948 and discredited by the International Mineralogical Association (IMA) in 2006.

References

Sulfate minerals Monoclinic minerals Minerals in space group 4 {{sulfate-mineral-stub