Buergerite Locality: Mexquitic, San Luis Potosí, Mexico (Locality at mindat.org) Size: cabinet, 15 x 12 x 4 cm Tourmaline var. Buergerite Buergerite is a rare m — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Fluor-buergerite
The fluorine-dominant tourmaline first found in rhyolitic cavities near Mexquitic, Mexico — originally just called buergerite.
Intro adapted from Wikipedia (CC BY-SA).
Fluor-buergerite is an IMA-recognized mineral species in the silicate class, with the chemical formula NaFe³⁺₃Al₆(Si₆O₁₈)(BO₃)₃O₃F.
It crystallizes in the hexagonal crystal system (space group R3m). It is a member of the Tourmaline structural group.
Key properties: Mohs hardness 7; specific gravity 3.31; typically brown or black or yellow; white streak; vitreous luster; refractive index 1.695; optically uniaxial.
IMA symbol Fbu, IMA status: approved, named in 1965.
Collections: Collector Favorites, Rare & Remarkable.