basaltic cavities

Formula: Na2Ca2(Si9Al6)O30.8H2O tectosilicate (framework silicate) zeolite group
Specific gravity: 2.26
Hardness: 5
Streak: White
Colour: Colourless, white, gray, yellowish

Hydrothermal environments
Basaltic cavities

Mesolite commonly occurs in cavities in volcanic rocks, typically basalt, also in andesite, porphyry (rock with coarse phenocrysts in a finer groundmass) and hydrothermal veins. In basaltic cavities it is generally in association with other zeolites.

In the vicinity of Meshkinshahr, Ardabil Province, Iran, mesolite is the most common zeolite, almost always associated with thomsonite and analcime.

In basaltic cavities in Oregon, USA, mesolite is associated with calcite, chabazite, analcime and stilbite.

Common impurity: K

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