Mineral - Xenotime-(Y)
Xenotime-(Y)
Chemical Properties
Mineral Class
Phosphates
Toxicity
radioactive
Formula
Y(PO₄)
Unit Cell
a=6.90 c=6.04 Z=4
Physical Properties
Hardness
4 - 5
Streak
white
Density
Heavy (3,5-6)
Cleavage
Imperfect after {100}
Fracture
splintery,
uneven
Tenacity
Brittle
Optical Properties
Color
browngrayyellow
Birefringence
0.107
Luster
Vitreous,
Resinous
Transparency
translucent,
transparent
Pleochroism
Geomineralogical Properties
Crystal System
tetragonal
Point Group
ditetragonal-dipyramidal - 4/m 2/m 2/m
Space Group
I4 1 /amd (141)
Habit
blocky, dipyramidal, prismatic, tabular
Formation
(1) Primarily magmatic, as an accessory mineral in acidic plutonic rocks (granites, pegmatites) and alkaline rocks, formed by the enrichment of yttrium and heavy rare earth elements in the residual melt.
(2) Metamorphic in gneisses or formed by hydrothermal mobilization in alpine-type fractures.
(3) Due to its high mechanical and chemical resistance in alluvial placer deposits
Paragenesis
Twinning
Rarity
Rarely
Synonyms
Xenotime-(Y)
Composition
Elements
Mass
P₂O₅
34.37
SiO₂
0.31
Y₂O₃
44.03
REE₂O₃
20.18
Norway (Palache et al. 1952)
Groups and Members
Xenotime-Group