Mineral - Polyakovite-(Ce)
Polyakovite-(Ce)
Chemical Properties
Mineral Class
Silicates
Toxicity
none
Formula
(Ce,Ca)₄(Mg,Fe²⁺)(Cr³⁺,Fe³⁺)₂(Ti,Nb)₂(Si₂O₇)₂O₈
Unit Cell
a=13,40 b=5,70 c=11,04 β=101° Z=2
Physical Properties
Hardness
5.5 - 6
Streak
brown
Density
Cleavage
keine
Fracture
conchoidal
Tenacity
Brittle
Optical Properties
Color
black
Birefringence
Luster
Vitreous
Transparency
translucent,
opaque
Pleochroism
Geomineralogical Properties
Crystal System
monoclinic
Point Group
Space Group
Habit
coarse, massive
Formation
Magmatisch, in Karbonatiten
Paragenesis
Twinning
Rarity
Very rare
Synonyms
Polyakovite-(Ce)
Composition
Elements
Mass
SiO₂
19,08
TiO₂
9,49
FeO
1,09
Fe₂O₃
4,30
MnO
0,05
MgO
2,61
CaO
1,06
Cr₂O₃
7,42
Nb₂O₅
3,98
ThO₂
2,79
UO₂
0,03
Y₂O₃
0,38
Ce₂O₃
24,24
La₂O₃
15,94
Nd₂O₃
4,76
Pr₂O₃
2,01
Sm₂O₃
0,38
H₂O
0,14
Russland
Groups and Members
Chevkinit-Gruppe