Baotite Locality: Sheep Creek, Mineral Point District, Ravalli County, Montana, USA ( Locality on mindat.org ) Size: 1.5 cm x 1.0 cm x 0.75 cm Two very nice, vitreous, vertically striated, blackish brown crystal fragments; one 7mm and the other 11mm in maximum dimension. This is an excellent example of this rare barium-titanium-niobium cyclosilicate. The label, from A. L. McGuiness, indicates aeschynite (?) in association. Ex. Rock Currier collection. Tom and Melissa Campbell photos. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Baotite
A rare barium-titanium silicate built on a unique four-fold silicate ring, its tetragonal crystals often deformed enough to look monoclinic.
Intro adapted from Wikipedia (CC BY-SA).
Baotite is an IMA-recognized mineral species in the silicate class, with the chemical formula Ba₄(Ti,Nb,W)₈O₁₆(SiO₃)₄Cl.
It crystallizes in the tetragonal crystal system (space group I4_1/a).
Key properties: Mohs hardness 6; specific gravity 4.42–4.71; Nearly semimetallic to vitreous luster; refractive index 1.97; optically uniaxial.
IMA symbol Bao, IMA status: approved, named in 1960.
Found in quartz veins cutting quartzite near alkalic granite and syenite (Baiyun-Obo mine, China); in a carbonate vein cutting \hornblende" gneiss intruded by diabase sills and small pegmatites (Ravalli Co., Montana, USA).
It is found associated with Quartz, calcite, aegirine, galena, pyrite, alkalic amphiboles (Baiyun-Obo mine, China); calcite, dolomite, ancylite, aeschynite, monazite, sodic amphiboles.
The name is derived from the locality, Pao-t'ou (Baotou in Russian), China.