Analcime

ANALCIME (from the Greek word "analkis", which means "weak", according to the weak electrization during the heating or friction * EN: analcite, analcime; DE: Analzim, Analcim, Analzit; FR: analcime; ES: analcima; RU: анальцим) is the rock-forming mineral of the subclass of the framework silicates, Na[AlSi206]•H2O. It is often included into the group of zeolites.

Common admixtures are: Ca, K, sometimes Cr, Be. It crystallizes into the cubic crystal systems. It may be found in the form of crystals (there are characteristic the polysynthetic twins), granular masses, small crusts, druses, geodes, fills the amygdules within the effusive rocks. It is mostly colourless and transparent, also white, grayish. The hardness is 5.5-6.0; brittle. The density is 2270±30 kilograms per cubic metre. It may be found within the alkaline and basic erupted rocks, within the nepheline-syenite pegmatites, within the volcanic tuffs, pumices, amygdaloidal lavas (basalts, traps, and others), and also within certain sedimentary rocks and soils.