Analcime (NaAlSi₂O₆·H₂O) is a sodium zeolite forming distinctive trapezohedral (24-sided) crystals — one of the diagnostic “cube-like” zeolites. Named from Greek “analkis” (weak) for its pyroelectric properties. Mt. Saint-Hilaire (Quebec) and Croft Quarry (England) yield iconic specimens. Forms in alkaline igneous rocks and basalt vesicles.
Key Facts
- Mohs hardness 5–5.5.
- Isometric; classic trapezohedral (24-sided) crystals are diagnostic.
- Colorless to white with vitreous luster.
- Member of the zeolite group, in alkaline igneous rocks and basalt.
- Pyroelectric — develops weak charge on heating.
Notable Localities
Mt. Saint-Hilaire (Quebec, Canada) supplies iconic gem-clear trapezohedrons. Croft Quarry (England) and Cyclopean Islands (Italy) yield additional specimens.
Found at these Localities
- Mont Saint-Hilaire (圣希莱尔山(魁北克))
- Italian Volcanic Province (Vesuvius / Lipari / Etna) (意大利火山矿物产地)
