Rutile

Physical Properties
Chemical Formula TiO2
Class Oxide
Crystal system Tetragonal
Habit Massive
Stubby to acicular tetragonal crystals
Striated prismatic crystals
Color Red
Red-brown to black
Hardness 6 to 6.5
Specific gravity 4.24
Cleavage/b> Good prismatic {100} and {110}
Fracture Subconchoidal
Luster Adamantine
Submetallic
Transparency Transparent to translucent
Streak Pale or light brown
Optical Properties
PPL Deep red, red-brown, or yellow-brown
Very high relief
XPL 3rd order colors
δ 0.29
Twinning Common
after Perkins, 370

Rutile in Thin Section

Rutile in hand sample (it’s the tiny black grain)

Rutilated quartz with ilmenite

Scanning electron micrograph of rutile needles (lighter color) exsolved on biotite

Rutile in Thin Section

Thin Section GigaPans

Rutile in plane polars

Rutile in crossed polars

Further Reading

Rutile at webmineral.com

Rutile at mindat.org