Outstanding tan and yellowish crystal aggregates of the very rare Sr-Ti silicate mineral ohmilite from the TL in Japan (Ohmi River, Ōmi, Itoigawa City, Niigata Prefecture, Honshu Island, Japan). Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY 4.0
Ohmilite
Ohmilite is an IMA-recognized mineral species in the silicate class, with the chemical formula Sr₃(Ti,Fe³⁺)(Si₂O₆)₂(O,OH)·2H₂O.
It crystallizes in the monoclinic crystal system (space group P2_1/m). It is a member of the Ohmilite structural group.
Key properties: Mohs hardness 3.5; specific gravity 3.38; White streak; optically biaxial.
IMA symbol Oh, IMA status: approved, named in 1973.
Found in an amphibolite-quartz-albitite dike cutting serpentinite.
It is found associated with Magnesio-riebeckite, quartz, albite, phlogopite, benitoite, bario-orthojoaquinite, leucosphenite.
The name is derived from the locality at Ohmi, Japan.