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| Name Origin | From the Greek leukos, meaning white |
|---|---|
| Chemical Formula | KAlSi2O6 |
| Color | Colorless, white, gray, yellowish |
| Hardness | 5.5 - 6 on Mohs Scale |
| Crystal System | Tetragonal. Crystals trapezohedral; granular |
| Cleavage | Poor. Fracture conchoidal. Brittle. |
| Specific Gravity (SG) | 2.47 - 2.50 |
| Pleochroism | None |
| Luster | Vitreous; dull on some crystals |
| Stone sizes |
Italian material has been cut to about 3 carats. There is very little of this material, always small and clean only in very tiny stones |
| Occurrence | In potassium-rich basic lavas |
Note: Leucite is abundant in various lava rocks but is extremely rare in facetable crystals. The material has little appeal except for its extreme scarcity. Stones often have a slight milky or cloudy look, and anything over 3 carats is likely to be included.
Leucite rock
"Leucite in rock w- nepheline Potassium aluminum silicate Albano Hills Italy 1927" by Dave Dyet https://www.shutterstone.com https://www.dyet.com - Own work. Licensed under Public Domain via Commons.
