Fluor-buergerite,[5] originally named 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.[2][3][4]

Fluor-buergerite
General
CategoryCyclosilicate
tourmaline
Formula
(repeating unit)
NaFe3+3Al6(BO3)3Si6O18(O,F,OH)4
IMA symbolFbu[1]
Strunz classification9.CK.05
Crystal systemTrigonal
Crystal classDitrigonal pyramidal (3m)
H-M symbol: (3m)
Space groupR3m
Identification
ColorBronze, Dark Brown, Black, Dark Purple
CleavageDistinct prismatic
Mohs scale hardness7
Streakyellowish brown
DiaphaneityTranslucent
Specific gravity3.31
Optical propertiesUniaxial (-)
Refractive indexnω = 1.735 nε = 1.655
Birefringenceδ = 0.080
Other characteristicsPyroelectric and piezoelectric
References[2][3][4]

References

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  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ a b Handbook of Mineralogy
  3. ^ a b Mindat
  4. ^ a b Webmineral data
  5. ^ Darrell J. Henry; Milan Novák; Frank C. Hawthorne; Andreas Ertl; Barbara L. Dutrow; Pavel Uher; Federico Pezzotta (2011). "Nomenclature of the tourmaline-supergroup minerals" (PDF). American Mineralogist. 96 (5–6): 895–913. Bibcode:2011AmMin..96..895H. doi:10.2138/am.2011.3636. S2CID 38696645. Archived from the original (PDF) on 2012-03-26. Retrieved 2012-04-18.