tetragonal Oxides
Rutile
Formula TiO2
Crystal Structure
#! Species: Rutile
#! System: Tetragonal (4/mmm)
#! Habit: Elongated prismatic with parallel striations
tetragonal[4/mmm]:{100}@1.0[striation:parallel] + {101}@0.6 | elongate(c:2.0)
tetragonal
4/mmm
{100} {101}
Quick Facts
Hardness
6.0
Specific Gravity
4.23
Refractive Index
2.616
Optical Character
Uniaxial +
Physical Properties
- Crystal System
- tetragonal
- Hardness (Mohs)
- 6.0
- Specific Gravity
- 4.23
- Cleavage
- Good prismatic {110}
- Fracture
- Subconchoidal to uneven
- Lustre
- Adamantine to metallic
Optical Properties
- Refractive Index
- 2.616
- Birefringence
- 0.287
- Optical Character
- Uniaxial +
- Dispersion
- 0.33
- Pleochroism
- moderate: Yellowish-brown / Reddish-brown (Distinct dichroism; visible in faceted stones and thin crystals)
Characteristics
Colours
Reddish-brownBlackGoldenRed (in transmitted light)
Localities
BrazilSwitzerlandUSA (Georgia, Virginia)NorwayAustralia
Common Inclusions
Twinning (knee twin, contact twin)Oriented overgrowths
Crystal Forms
tetragonal_prismtetragonal_dipyramid
Notes
Extreme birefringence (0.287) and dispersion (0.330) - among highest of any mineral; synthetic rutile once used as diamond simulant (Titania)
Related Minerals
Other minerals in the tetragonal system
