Cossaite
Cossaite is an IMA-recognized mineral species in the sulfate class, with the chemical formula (Mg₀.₅, )Al₆(SO₄)₆(HSO₄)F₆·36H₂O.
It crystallizes in the hexagonal crystal system (space group R-3).
Key properties: specific gravity 2.08; White streak; Vitreous luster.
IMA symbol Css, IMA status: approved, named in 2009.
A rare phase formed at approximately 350oC by vapor alteration of volcanic breccia in a strongly acidic, fluorine-rich environment.
It is found associated with Thermessaite, vlodavetsite, sassolite, salammoniac.
The mineral was named to honor Alfonso Cossa (1833–1902), an Italian chemist and mineralogist.
Index entry. This entry combines official IMA/RRUFF species data with published physical-property data — a full written entry hasn’t been published yet.
Browse more C minerals or help write this entry.