Mineral - Rutile
Rutile
Chemical Properties
Mineral Class
Oxides and Hydrxides
Toxicity
none
Formula
TiO₂
Unit Cell
a=4.59 c=2.96 Z=2
Physical Properties
Hardness
6 - 6.5
Streak
brown
Density
Heavy (3,5-6)
Cleavage
Distinct after {110}, indistinct after {100}
Fracture
conchoidal,
uneven
Tenacity
Brittle
Optical Properties
Color
blackbrownredyellow
Birefringence
0.294
Luster
Adamantine
Transparency
translucent,
transparent,
opaque
Pleochroism
Rot-Braun-Gelb-Grün
Geomineralogical Properties
Crystal System
tetragonal
Point Group
ditetragonal-dipyramidal - 4/m 2/m 2/m
Space Group
P4 2 /mnm (136)
Habit
hair-like, acicular, prismatic, skeletal, tabular
Formation
(1) Primarily magmatic in silica-rich intrusive rocks, as well as in alkaline volcanic rocks and pegmatites.
(2) Metamorphic under high-pressure and high-temperature conditions, in eclogites and blue schists through the alteration of titanium-bearing minerals.
(3) Due to its high mechanical and chemical resistance, in alluvial placer deposits.
Paragenesis
Twinning
V-shaped contact twins after {011}, six- and eight-fold rotational twins after {011}, wedge-shaped contact twins after {031},
Rarity
Common
Synonyms
Rutile
Composition
Elements
Mass
TiO₂
97.46
Fe₂O₃
2.62
Georgia (Palache et al. 1952)
Groups and Members
Rutile-Group