mineral

Stilbite zeolite specimen

Stilbite, commonly Ca- or Na-rich zeolite: (Ca,Na)₂–₃Al₃(Al,Si)₂Si₁₃O₃₆·12H₂O

AI-generated identification · may be incorrect

White to cream, pearly-to-vitreous radiating blades with prominent cleavage; Mohs hardness 3.5–4, low specific gravity (~2.1–2.2), and typically monoclinic crystal structure. The specimen appears to be stilbite crystals lining a porous volcanic matrix, possibly with associated calcite or other zeolites.

Identified August 14, 2026More mineral →

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Physical properties

Formation & geological history

Forms as a low-temperature hydrothermal mineral in cavities and fractures of basaltic volcanic rocks, often through alteration of volcanic glass. Most collectible material formed in Cenozoic volcanic provinces, although zeolites occur in rocks of many ages.

Uses & applications

Primarily a collector and display mineral; zeolites also have industrial uses as molecular sieves, water softeners, catalysts, and absorbents. This delicate specimen is generally unsuitable for construction or jewelry.

Geological facts

Stilbite commonly develops distinctive bow-tie, sheaf, or radiating aggregates and can show a silky or pearly sheen. It is especially abundant in Indian basalt cavities, where large cream-colored specimens are commercially collected.

Field identification & locations

Identify it by soft, light-colored radiating blades in basalt cavities, pearly luster, and easy scratching with a steel blade; acid testing may reveal associated calcite rather than stilbite itself. Estimated value: about $10–$50 for a small common specimen, or $75–$200+ for large, sharply crystallized pieces.