monoclinic Nesosilicates
Sphene (Titanite)
Formula CaTiSiO5
Crystal Structure
#! Species: Sphene (Titanite)
#! System: Monoclinic (2/m)
#! Habit: Characteristic wedge shape with extreme dispersion
monoclinic[2/m]:{100}@1.0[pleochroism:strong] + {110}@0.6 + {111}@0.5 + {001}@0.3
monoclinic
2/m
{100} {110} {111} {001}
Quick Facts
Hardness
5.0
Specific Gravity
3.52
Refractive Index
1.9
Optical Character
Biaxial +
Physical Properties
- Crystal System
- monoclinic
- Hardness (Mohs)
- 5.0
- Specific Gravity
- 3.52
- Cleavage
- Distinct {110}
- Fracture
- Subconchoidal
- Lustre
- Adamantine to resinous
Optical Properties
- Refractive Index
- 1.9
- Birefringence
- 0.100-0.160
- Optical Character
- Biaxial +
- Dispersion
- 0.051
- Pleochroism
- moderate: Colourless to yellow / Greenish-yellow / Reddish-yellow (Moderate trichroism; often masked by high dispersion)
Characteristics
Colours
YellowGreenBrownOrangeRed (rare)Colorless (rare)
Localities
BrazilMadagascarPakistan (gem quality)Austria (Alps)CanadaMexico
Crystal Forms
wedge (characteristic)pinacoidprism
Diagnostic Features
Very high dispersion (0.051); strong birefringence; adamantine lustre; monoclinic wedge-shaped
Notes
Dispersion exceeds diamond; high birefringence causes visible facet doubling; too soft for everyday wear
Related Minerals
Other minerals in the monoclinic system
