Mineral Information and Data:

Buergerite
NaFe3+3Al6(BO3)3Si6O18O3F [CNMNC approved formula]

Named for Martin J. Buerger (1903-1986), a Professor of Mineralogy at the Massacusetts Institute of Technology and a pioneer of crystal structure analysis, he invented the X-ray precession camera permitting undistorted photography of the reciprocal lattice.

IMA status : Approved Species 1966 (IMA1965-005)
CLASSIFICATION 
Dana
(8th edition) :
61.03c.01.05  (This Dana# Changed)
  (61) Cyclosilicate Six-Membered Rings
  (61.03c) with borate groups (Ferric Tourmaline Subgroup)
  (61.03c.01) Buergerite Subgroup
  
Nickel-Strunz
(10th edition) :
09.CK.05
  (09) Silicates
  (09.C) Cyclosilicates
  (09.CK) [Si6O18]12- branched 6-membered single rings, with insular complex anions
  
Crystal system: Trigonal System
Point group (H-M): 3m — ditrigonal-pyramidal
Unit cell: a = 15.87Å, c = 7.18Å
Crystal Habit: Crystals short prismatic
  
Color: Dark brown, black; bronze schiller
Diaphaneity: Translucent
Luster: Vitreous
Hardness (Mohs): 7
Measured Density: 3.31 g/cm3
Cleavage: Distinct prismatic
Tenacity: Brittle
Streak: Yellow-brown
  
Geologic Setting: Of probable pneumatolytic origin, in cavities in a rhyolite.
Mineral Association: Quartz, potassic feldspar, plagioclase, biotite, muscovite
  
Other Properties: Piezoelectric. Pyroelectric. Gemstone Unlikely Available.

 

Buergerite
Origin: San Luis Potosi, Mexico
Sample size: 3 x 3 x 2 cm, crystal 1.2 cm
Photo: Tom Loomis

 

Buergerite
(zoom-in of above)

 

Buergerite
Origin: Mexquitic, San Luis Potosi, Mexico
Sample size: 6.7 x 3.7 x 2.8 cm
Photo: Rob Lavinsky

 

Buergerite
(zoom-in of above)

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