
Analcime: Gemstone Information
Small colorless transparent crystals of analcime have occasionally been cut. Analcime, a mineral of the zeolite group, forms icositetrahedral crystals of the cubic system and has the composition NaAlSi2O6H2O. The hardness is from 5 to 5.5, the SG ranges from 2.22 to 2.29 and the RI is 1.487. Though analcime is found world-wide, the most likely source for the occasional colorless-faceted stone is Mt Saint Hilaire, Quebec, Canada; some colored material with RI 1.530–1.536 and 1.532–1.538 has been produced there. Crystals, including specimens from Croft Quarry, Leicester, England, are often well formed and collectable.