Heulandite

Heulandite is a mineral from the zeolite group, composed of a hydrous silicate of calcium, sodium, and aluminum. It appears as tabular or prismatic crystals, often with a characteristic pearly luster. Its colors vary from white, colorless, and grey to pink, yellow, brown, or pale green.

It primarily forms in cavities of volcanic rocks, often associated with stilbite, apophyllite, chabazite, or scolecite. Specimens from Maharashtra (India) are particularly known for their well-developed crystals and spectacular associations with other zeolites.