Mineral - Elbaite
Elbaite
Chemical Properties
Mineral Class
Silicates
Toxicity
none
Formula
Na(Li₁,5Al₁,5)Al₆(Si₆O₁₈)(BO₃)₃(OH)₃(OH)
Unit Cell
a=15.90 c=7.10 Z=3
Physical Properties
Hardness
7 - 7.5
Streak
white
Density
Normal (2-3,5)
Cleavage
Indistinct after {11 2 0} and {10 1 1}
Fracture
uneven
Tenacity
Brittle
Optical Properties
Color
redyellowgreenblueviolet
Birefringence
0.021
Luster
Vitreous
Transparency
translucent,
transparent
Pleochroism
Teilweise stark, in verschiedensten Farbvarianten
Geomineralogical Properties
Crystal System
trigonal
Point Group
ditrigonal-pyramidal - 3m
Space Group
R3m (160)
Habit
granular, acicular, prismatic
Formation
Metamorphism, Magmatic
Paragenesis
Twinning
Rarity
Common
Synonyms
Elbaite
Composition
Elements
Mass
SiO₂
37.89
TiO₂
0.04
B₂O₃
10.28
Al₂O₃
43.85
FeO
0.11
MnO
0.11
CaO
0.07
Li₂O
1.66
Na₂O
2.43
F
0.10
H₂O
3.47
Italy (Dana 1895)
Groups and Members
Tourmaline-Group