Tokyoite ore displayed at Mining Museum of Akita University — Photo: 掬茶 · CC BY-SA 4.0
Tokyoite
A rare barium-manganese vanadate — the manganese analogue of gamagarite.
Intro adapted from Wikipedia (CC BY-SA).
Tokyoite is an IMA-recognized mineral species in the vanadate class, with the chemical formula Ba₂Mn³⁺(VO₄)₂OH.
It crystallizes in the monoclinic crystal system (space group P2_1/m). It is a member of the Brackebuschite structural group.
Key properties: Mohs hardness 4–4.5; specific gravity 4.62; Dark brownish red streak; Vitreous luster.
IMA symbol Tky, IMA status: approved, named in 2003.
From an outcrop, in an abandoned Mn deposit in brecciated braunite and in veinlets in chert blocks enclosed in sandstone in an accretionary complex.
It is found associated with Braunite, hyalophane, tamaite.
The name refers to the metropolitan area containing the first locality.