Medaite Locality: Molinello Mine, Graveglia Valley, Ne, Genova Province , Liguria , Italy ( Locality at mindat.org ) Size: 5.9 x 3.2 x 1.8 cm. A thin drusy crust on matrix is the very rare mineral medaite: a manganese, calcium, vanadium arsenic, silicate hydroxide. The medaite has sparkling luster and a rose red color. This specimen is from the type locality in Italy and is, I am told, quite rich for the species. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Medaite
Medaite is an IMA-recognized mineral species in the silicate class, with the chemical formula Mn²⁺₆V⁵⁺Si₅O₁₈(OH).
It crystallizes in the monoclinic crystal system (space group P2_1/n). It is a member of the Medaite structural group.
Key properties: specific gravity 3.7; Subadamantine luster; optically biaxial.
IMA symbol Med, IMA status: approved, named in 1979.
Formed at low temperature and low H2O fugacity in veinlets cutting manganese ores.
It is found associated with Tiragalloite, braunite, quartz, manganoan calcite, parsettensite, albite (Molinello mine, Italy); palenzonaite, saneroite, pyrobelonite, fianelite.
The mineral was named to honor Dr. Francesco Meda (1926–1977), an amateur mineralogist from Turin, Italy.