Mineral - Pezzottaite-(Cs)
Pezzottaite-(Cs)
Chemical Properties
Mineral Class
Silicates
Toxicity
none
Formula
Cs(Be₂Li)Al₂(Si₆O₁₈)
Unit Cell
a=15.95 c=27.80 Z=18
Physical Properties
Hardness
8
Streak
white
Density
Normal (2-3,5)
Cleavage
Imperfect after {001}
Fracture
conchoidal,
uneven
Tenacity
Brittle
Optical Properties
Color
redorangepinkorange red
Birefringence
0.011
Luster
Vitreous
Transparency
translucent,
transparent
Pleochroism
Orange-Rot-Violett
Geomineralogical Properties
Crystal System
trigonal
Point Group
rhombohedral - 3
Space Group
R 3 (148)
Habit
prismatic, tabular, barrel-shaped
Formation
Magmatic, in the late hydrothermal stage of LCT-type (lithium-cesium-tantalum) granit pegmatite fractionation, by hydrothermal crystallization in miarolitic cavities
Paragenesis
Twinning
Rarity
Very rare
Synonyms
Pezzottaite-(Cs)
Composition
Elements
Mass
SiO₂
54.58
TiO₂
0.01
Al₂O₃
16.88
FeO
0.02
MnO
0.02
CaO
0.22
Na₂O
0.46
K₂O
0.14
Rb₂O
0.44
Cs₂O
18.23
Li₂O
2.12
BeO
8.14
H₂O
0.28
Madagascar (Laurs et al. 2003)
Groups and Members
Beryl-Supergroup
Beryl-Group