Mineral - Jeremejevite
Jeremejevite
Chemical Properties
Mineral Class
Borates
Toxicity
none
Formula
Al₆[(F,OH)₃|(BO₃)₅]
Unit Cell
a=8.56 c=8.18 Z=2
Physical Properties
Hardness
6.5 - 7.5
Streak
white
Density
Normal (2-3,5)
Cleavage
Fracture
conchoidal
Tenacity
Brittle
Optical Properties
Color
whiteyellowbluecolorless
Birefringence
0.013
Luster
Vitreous
Transparency
transparent
Pleochroism
Geomineralogical Properties
Crystal System
hexagonal
Point Group
hexagonal-dipyramidal - 6/m
Space Group
P6 3 /m (176)
Habit
acicular, prismatic
Formation
As a late magmatic-hydrothermal mineral in highly fractionated, boron-rich granitic pegmatites through crystallization from residual melts or fluid-rich phases
Paragenesis
Twinning
Rarity
Rarely
Synonyms
Jeremejevite
Composition
Elements
Mass
SiO₂
0.03
B₂O₃
33.51
Al₂O₃
59.90
Fe₂O₃
0.01
F
10.18
O=F₂
4.29
Russland (Palache et al. 1952)