Sky blue crystals of the rare sulphate mineral magnesioaubertite from the type locality and only one of the two known localities worldwide: Faraglione Ranni, Vulcano Island, Lipari, Sicily, Italy. — Photo: David Hospital · CC BY-SA 4.0
Magnesioaubertite
Magnesioaubertite is an IMA-recognized mineral species in the sulfate class, with the chemical formula MgAl(SO₄)₂Cl·14H₂O.
It crystallizes in the triclinic crystal system (space group P-1). It is a member of the Aubertite structural group.
Key properties: Mohs hardness 2–3; specific gravity 1.8; White streak; Vitreous luster; optically biaxial.
IMA symbol Maub, IMA status: approved, named in 1982.
A rare secondary mineral formed by the reaction of volcanic gases and aluminum-bearing rocks.
It is found associated with Alunogen, pickeringite, metasideronatrite, sulfur, tamarugite, aluminocopiapite, metavoltine.
The name refers to its content of magnesium greater than copper, and relation to aubertite.