Tiragalloite Locality: Molinello Mine, Graveglia Valley, Ne, Genova Province , Liguria , Italy ( Locality at mindat.org ) Orange Tiragalloite crystals on Ganophyllite. Field of view 5mm. Specimen and photo Leon Hupperichs. — Photo: Leon Hupperichs · CC BY-SA 3.0
Tiragalloite
Tiragalloite is an IMA-recognized mineral species in the silicate class, with the chemical formula Mn²⁺₄As⁵⁺Si₃O₁₂(OH).
It crystallizes in the monoclinic crystal system (space group P2_1/n).
Key properties: specific gravity 3.84; Subadamantine luster; optically biaxial.
IMA symbol Tga, IMA status: approved, named in 1979.
Found in veinlets cutting massive aggregates of braunite and quartz (Molinello mine, Italy); in manganese-rich lenses in quartzitic chlorite schists probably derived from marine sediments (KÄo dnitz Valley, Austria).
It is found associated with Quartz, manganoan calcite, parsettensite, albite, medaite (Molinello mine, Italy); tephroite, pyroxmangite, rhodonite, spessartine.
The name refers to Paolo Tiragallo (1905{), amateur mineralogist of Liguria, Italy.