Ambrinoite

Ambrinoite is a very rare new mineral (IMA 2009-071) that is found only in this locality worldwide (Signols Quarry, Signols, Oulx, Val di Susa, Piedmont, Italy), so it's a one locality mineral. In addition, it is the first K- NH4 sulfosalt, which add interest to the species: Biagioni, C. et al. (2011): Ambrinoite, (K,NH4)2(As,Sb)8S13•H2O, a new mineral from Upper Susa Valley, Piedmont, Italy: the first natural (K,NH4)-hydrated sulfosalt. American Mineralogist, 96, 878-887. — Photo: David Hospital · CC BY-SA 4.0

Ambrinoite

Ambrinoite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula [K,(NH₄)]₂(As,Sb)₆(Sb,As)₂S₁₃·H₂O.

It crystallizes in the triclinic crystal system (space group P-1).

Key properties: Mohs hardness 2; specific gravity 3.276; Reddish streak; Vitreous to resinous luster.

IMA symbol Amb, IMA status: approved, named in 2009.

Found in an evaporite deposit probably formed by highly alkaline, low-temperature hydrothermal fluids.

It is found associated with Sulfur, orpiment, gypsum.

The mineral was named to honor Pierluigi Ambrino (b. 1947), the mineral collector who provided the specimens.