Mineral - Davidite-(La)
Davidite-(La)
Chemical Properties
Mineral Class
Oxides and Hydrxides
Toxicity
none
Formula
La(Y,U)Fe₂(Ti,Fe,Cr,V)₁₈(O,OH,F)₃₈
Unit Cell
a=10.32 c=20.85 Z=3
Physical Properties
Hardness
6
Streak
blackbrown
Density
Heavy (3,5-6)
Cleavage
Fracture
conchoidal
Tenacity
Brittle
Optical Properties
Color
blackbrowngray
Birefringence
Luster
Vitreous,
Greasy
Transparency
opaque
Pleochroism
Geomineralogical Properties
Crystal System
trigonal
Point Group
rhombohedral - 3
Space Group
R 3 (148)
Habit
coarse, massive, prismatic, tabular
Formation
Magmatic, in pegmatites
Paragenesis
Twinning
Rarity
Rarely
Synonyms
Davidite-(La), Davidite
Composition
Elements
Mass
V₂O₅
2.88
TiO₂
51.74
ZrO₂
0.07
HfO₂
0.51
ThO₂
0.05
UO₂
6.42
Al₂O₃
0.22
Y₂O₃
1.86
La₂O₃
3.35
CeO₂
3.06
Nd₂O₃
0.35
Fe₂O₃
25.30
Cr₂O₃
1.21
MnO
0.04
PbO
0.69
MgO
0.10
CaO
0.23
SrO
0.02
Australia (Palache et al. 1952)
Groups and Members
Crichtonite-Group