Sharp cubic black crystals of apuanite from the type and only known locality worldwide: Buca Della Vena Mine, Apuan Alps, Lucca Province, Tuscany, Italy. — Photo: David Hospital · CC BY-SA 4.0
Apuanite
A rare iron-antimony oxysulfide first found in Italy's Province of Lucca.
Intro adapted from Wikipedia (CC BY-SA).
Apuanite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula (Fe²⁺Fe³⁺₂)(Fe³⁺₂Sb³⁺₄)O₁₂S.
It crystallizes in the tetragonal crystal system (space group P4_2/mbc). It is a member of the Trippkeite structural group.
Key properties: specific gravity 5.33; Metallic luster.
IMA symbol Apu, IMA status: approved, named in 1978.
Found in an iron deposit in barite formed by low-grade metasomatic processes at the contact between phyllites and dolostones.
It is found associated with Versiliaite, barite, magnetite, hematite, pyrite.
The name refers to the Apuan Alps, Italy, where it was found.