Mineral - Stillwellite-(Ce)
Stillwellite-(Ce)
Chemical Properties
Mineral Class
Silicates
Toxicity
radioactive
Formula
(Ce,La,Ca)BSiO₅
Unit Cell
a=6,84 c=6,70 Z=3
Physical Properties
Hardness
6.5
Streak
white
Density
Cleavage
Unvollkommen
Fracture
conchoidal
Tenacity
Optical Properties
Color
browngrayorangeyellow
Birefringence
0,015
Luster
Vitreous,
Greasy
Transparency
translucent,
transparent
Pleochroism
Geomineralogical Properties
Crystal System
trigonal
Point Group
Space Group
Habit
Octahedron, prismatic, Rhombohedron, tabular
Formation
In alkalischen Pegmatiten von Syeniten
Paragenesis
Twinning
Rarity
Rarely
Synonyms
Stillwellite-(Ce)
Composition
Elements
Mass
SiO₂
22,40
UO₂
0,01
ThO₂
0,03
B₂O₃
12,33
Al₂O₃
0,42
Y₂O₃
0,74
La₂O₃
27,95
Ce₂O₃
33,15
Pr₂O₃
0,01
Nd₂O₃
0,01
Sm₂O₃
0,01
Fe₂O₃
0,18
MgO
0,06
CaO
0,95
F
0,30
H₂O
0,95
P₂O₅
0,67
Australien