Leucite
Mineral KAlSi2O6
About it
Trapezohedra that look like garnet but are white and far lighter, set in the lavas of Vesuvius and the Alban Hills; they grow cubic and turn tetragonal on cooling.
- Type
- Mineral
- Group
- Silicate (tectosilicate), leucite group
- Formula
- KAlSi2O6
- Hardness (Mohs)
- 5.5–6
- Specific gravity
- 2.45–2.5
- Streak
- white
- Lustre
- vitreous (glassy)
- Crystal system
- Tetragonal
- Colours
- white, grey, colourless
- Transparency
- transparent, translucent, opaque
- Cleavage and fracture
- poor; conchoidal fracture
Typical values: real specimens vary. For more, see mindat.org.