Tamaite ore exhibited at the Mining Museum of Akita University — Photo: 掬茶 · CC BY-SA 4.0
Tamaite
Tamaite is an IMA-recognized mineral species in the silicate class, with the chemical formula (Ca,K,Na)ₓMn₆(Si,Al)₁₀O₂₄(OH)₄·nH₂O (x = 1-2; n = 7-11).
It crystallizes in the orthorhombic crystal system (space group Pnma).
Key properties: Mohs hardness 4; specific gravity 2.85; White streak; Vitreous to pearly luster; optically biaxial.
IMA symbol Tam, IMA status: approved, named in 1999.
Found in veinlets to 1.5 mm in width in a weakly metamorphosed Mn ore deposit.
It is found associated with Celsian, barian orthoclase, aegirine, manganoan grossular, andradite, strontiopiemontite, copper.
The name is derived from the locality, the Tama district, where the first samples were collected.