Mineral - Zircon
Zircon
Chemical Properties
Mineral Class
Silicates
Toxicity
none
Formula
Zr(SiO₄)
Unit Cell
a=6.61 c=5.98 Z=4
Physical Properties
Hardness
7.5
Streak
white
Density
Heavy (3,5-6)
Cleavage
Indistinct after {110} and {111}
Fracture
conchoidal
Tenacity
Brittle
Optical Properties
Color
blackbrownredyellowgreen
Birefringence
0.055
Luster
Vitreous,
Adamantine
Transparency
translucent,
transparent,
opaque
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, granular, prismatic
Formation
(1) Primarily magmatic, formed by crystallization from silicate melts as an accessory mineral in acidic to intermediate plutonic and volcanic rocks.
(2) Metamorphic, formed by recrystallization under high pressure and temperature conditions.
(3) Due to its high mechanical and chemical resistance, found in alluvial placer deposits
Paragenesis
Twinning
Rarity
Common
Synonyms
Zircon
Composition
Elements
Mass
SiO₂
32.86
ZrO₂
66.72
HfO₂
1.15
ThO₂
0.01
U₃O₈
0.03
India (Dana 1895)
Groups and Members
Zircon-Group