Jeremejevite

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
Jeremejevite
Jeremejevite-273102.jpg
General
CategoryBorate mineral
Formula
(repeating unit)
Al6B5O15(F,OH)3
Strunz classification6.AB.15
Crystal systemHexagonal
Crystal classDipyramidal class (6/m)
H-M symbol: (6/m)
Space groupP63/m
Unit cella = 8.5591(3),
c = 8.1814(6) [Å]; Z = 2
Identification
ColorColorless, white, yellowish, blue
Crystal habitPrismatic
CleavageNone observed
FractureConchoidal
Mohs scale hardness6.5 - 7.5
LusterVitreous
StreakWhite
DiaphaneityTransparent
Specific gravity3.28 - 3.31
Optical propertiesUniaxial (-)
Refractive indexnω = 1.653 nε = 1.640
Birefringence0.0130
PleochroismColorless - light blue-violet
Other characteristicsPiezoelectric
References[1][2][3]

Jeremejevite is a rare aluminium borate mineral with variable fluoride and hydroxide ions. Its chemical formula is Al6B5O15(F,OH)3.

It was first described in 1883[4] for an occurrence on Mt. Soktui, Nerschinsk district, Adun-Chilon Mountains, Siberia. It was named after Russian mineralogist Pavel Vladimirovich Eremeev (Jeremejev, German) (1830–1899).[3]

It occurs as a late hydrothermal phase in granitic pegmatites in association with albite, tourmaline, quartz and rarely gypsum. It has also been reported in the Pamir Mountains of Tajikistan, Namibia and the Eifel district, Germany.[3]

Blue jeremejevite in rare, clear crystal form. Image width: 1.5 mm.

References[edit]

  1. ^ Jeremjevite on Mindat.org
  2. ^ Jeremejevite on Webmineral.com
  3. ^ a b c Handbook of Mineralogy
  4. ^ Damour A. Note sur un borate d'alumine cristallisé de la Siberie. Nouvelle espèce minerale // Bulletin de la Societe mineralogique de France. 1883. 6. N 1. P. 20-23.