Jeremejevite
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Jeremejevite is an aluminium borate mineral with variable fluoride and hydroxide ions. Its chemical formula is Al6B5O15(F,OH)3. It is considered as one of the rarest, thus one of the most expensive stones. For nearly a century, it was considered as one of the rarest gemstones in the world.[5][better source needed]
Quick Facts General, Category ...
Jeremejevite | |
---|---|
General | |
Category | Borate mineral |
Formula (repeating unit) | Al6B5O15(F,OH)3 |
IMA symbol | Jer[1] |
Strunz classification | 6.AB.15 |
Crystal system | Hexagonal |
Crystal class |
|
Space group | P63/m |
Identification | |
Color | Colorless, white, yellowish, blue, light yellow brown, aquamarine blue, rarely violet; colourless in transmitted light |
Crystal habit | Prismatic |
Cleavage | None observed |
Fracture | Conchoidal |
Mohs scale hardness | 6.5 – 7.5 |
Luster | Vitreous |
Streak | White |
Diaphaneity | Transparent |
Specific gravity | 3.28 – 3.31 |
Optical properties | Uniaxial (-) |
Refractive index | nω = 1.653 nε = 1.640 |
Birefringence | 0.0130 |
Pleochroism | Colorless – light blue-violet |
Other characteristics | Piezoelectric |
References | [2][3][4] |
Close
It was first described in 1883[6] as small, single crystals in loose granitic debris in Mt. Soktui, Nerschinsk district, Adun-Chilon Mountains, Siberia.[7] It was named after Pavel Vladimirovich Eremeev, Russian mineralogist, engineer and professor, who collected the first specimens (Jeremejev, German; 1830–1899).[4]