mineral

Stilbite

Stilbite-Ca (NaCa4(Si27Al9)O72·28H2O)

Hardness: 3.5-4 on Mohs scale; Color: White, cream, or peach; Luster: Pearly to vitreous; Crystal Structure: Monoclinic (often forming bow-tie shaped aggregates); Cleavage: Perfect in one direction; Specific Gravity: 2.1-2.2

Hardness: 3
Color: White, cream, or peach
Luster: Pearly to vitreous

Identified May 22, 2026More mineral →

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Physical properties

Formation & geological history

Commonly forms as a secondary mineral in volcanic rocks, specifically within the cavities (vesicles) of basalt or andesite through hydrothermal activity. Frequently associated with other zeolites.

Uses & applications

Primarily used as a collector specimen; also utilized in industrial water softening and as a molecular sieve due to its zeolite properties.

Geological facts

The name comes from the Greek word 'stilbein,' meaning 'to shine,' referring to its pearly luster. It is particularly famous for forming 'bow-tie' or 'hourglass' shaped clusters.

Field identification & locations

Identify in the field by its distinct sheaf-like or bow-tie crystal habits and pearly luster on cleavage surfaces. Commonly found in the Deccan Traps of India, Iceland, and the Faroe Islands.