- Group
- Silicates - tectosilicates
- Composition
- SiO2
- Formula
- SiO2
- Color
- Violet
- Crystal system
- Hexagonal / trigonal
- Crystal habit
- Usually pyramidal terminations; occasionally prismatic.
- Hardness
- 7
- Fracture
- Conchoidal
- Cleavage
- None
- Luster
- Vitreous
- Streak
- White
- Transparency
- From opaque to translucent
- Specific gravity
- 2.7
- Refractive index
- 1.54 - 1.55
