Analcime: Gemstone Information

Small colourless transparent crystals of analcime have occasionally been cut. Analcime, a mineral of the zeolite group, forms icositetrahedral crys-tals 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 sourcefor the occasional colourless-faceted stone is Mt Saint Hilaire, Quebec,Canada; some coloured material with RI 1.530–1.536 and 1.532–1.538 hasbeen produced there. Crystals, including specimens from Croft Quarry,Leicester, England, are often well formed and collectable.