| Buergerite | |
|---|---|
| General | |
| Category | Cyclosilicate |
| Chemical formula | NaFe3+3Al6(BO3)3Si6O18(O,F,OH)4 |
| Identification | |
| Color | Bronze, dark brown, black |
| Crystal system | Trigonal - ditrigonal pyramidal (3m) |
| Cleavage | Distinct prismatic |
| Mohs scale hardness | 7 |
| Streak | yellowish brown |
| Diaphaneity | Translucent |
| Specific gravity | 3.31 |
| Optical properties | Uniaxial (-) |
| Refractive index | nω = 1.735 nε = 1.655 |
| Birefringence | δ = 0.080 |
| Other characteristics | Pyroelectric and piezoelectric |
| References | [1][2][3] |
Buergerite is a mineral species belonging to the tourmaline group. It was first described for an occurrence in rhyolitic cavities near Mexquitic, San Luis Potosi, Mexico. It was approved as a mineral in 1966 by the IMA and named in honor of Martin J. Buerger (1903-1986) Professor of Mineralogy at the Massachusetts Institute of Technology. It has also been reported from Minas Gerais, Brazil, and the Central Bohemia Region of the Czech Republic.[1][2][3]