Buergerite - Encyclopedia
Class : Silicates
Subclass : Cyclosilicates
Crystal system : Rhombohedral
Chemistry : NaFe3Al6(BO3)3Si6O18(O,F,OH)4
Rarity : Very rare
Buergerite, recently renamed fluor-buergerite, is the rarest of the tourmalines. It was named in honor of crystallographer Martin Julian Buerger, professor of mineralogy at MIT. It is a mineral of hydrothermal origin, like the other minerals of the group, it forms short to elongated, strongly fluted prismatic crystals, measuring up to 4 cm, frequently united in radiating groups. It is dark brown to black in color.
Main photo : Fluor-buergerite from Mexquitic from Carmona Municipality, San Luis Potosí, Mexico © Kevin Conroy
Twinning
No known twin for this mineral species.
Fakes and treatments
No fake identified for this mineral species.
Hardness : 7
Density : 3.3
Fracture : Conchoidal
Streak : Light brown
TP : Translucent to opaque
RI : 1.655 to 1.735
Birefringence : 0,080
Optical character : Uniaxial -
Pleochroism : Visible
Fluorescence : None
Solubility : Insoluble
Magnetism : None
Radioactivity : None