# Stilbite

- Page: https://taslar.bumba.tr/en/stones/stilbite/
- Turkish: Stilbit
- Also known as: Desmine (older name, still used in Germany)
- Kind: Mineral
- Classification: Minerals › Silicates › Tectosilicates
- Chemical formula: NaCa₄(Si₂₇Al₉)O₇₂·28H₂O
- Crystal system: Monoclinic
- Hardness (Mohs): 3.5–4
- Specific gravity: 2.19–2.23 g/cm³
- Lustre: Vitreous (glassy), Pearly
- Transparency: Transparent, Translucent
- Colours: white, yellowish, grey, pink, reddish, orange, light to dark brown
- Streak: White
- Cleavage: Perfect on {010}
- Fracture: Uneven; brittle
- Value ladder: 2/9 step, Raw material by the tonne
- Last checked: 2026-10-04

A pearly zeolite that grows in bow-ties and sheaves: the pink jewel of India's basalts.

Stilbite is a common zeolite mineral made of sodium, calcium, aluminium, silicon, oxygen and water. Its calcium-rich species is called stilbite-Ca and its sodium-rich species stilbite-Na. Its thin, plate-like crystals are white, pink, orange or brown and often form groups shaped like sheaves of wheat or bow-ties. Its name comes from the Greek stilbein, “to shine”, because of the pearly lustre of its faces. The world's most prolific source is the Deccan basalts of India.

## How does it form?

Stilbite forms from low-temperature hot water solutions (hydrothermally). It crystallises in the gas cavities of volcanic rocks such as basalt and andesite and in cavities of various metamorphic rocks. It also forms in hot spring deposits, and in some sandstones and conglomerates it acts as the cement binding the grains together. It occurs with other zeolites, prehnite, calcite and quartz.

According to the Handbook of Mineralogy, stilbite is a common zeolite with many occurrences of large, fine crystals: Teigarhorn and Helgustaðir in Iceland, the Faroe Islands, the Glasgow district in Scotland, Paterson and Great Notch in New Jersey, the Bay of Fundy in Canada and Rio Grande do Sul in Brazil are among them. Exceptional crystals come from the Mumbai, Pune and Nashik districts of India.

## What is it used for?

- **Collecting:** Its pink, bow-tie-shaped crystal groups are much loved by collectors.
- **Natural cement:** In some sandstones and conglomerates it is the cement that holds the grains together.

## How to recognise it

- Its crystals are thin plates, often in groups shaped like a sheaf of wheat or a bow-tie, pinched in the middle.
- White, pink, salmon, orange or brown; its cleavage faces have a pearly lustre.
- Light (specific gravity about 2.2), with a hardness of 3.5–4.
- Found in cavities in basalt and andesite with other zeolites, prehnite, calcite and quartz.

## Fakes and imitations

- Heulandite is also a plate-like, pearly zeolite and can occur in the same cavities; a certain distinction is made in the laboratory.

## What determines its value?

Stilbite is a common and relatively inexpensive collector's mineral. Its value depends on the size and colour of the crystal groups, a well-formed bow-tie or sheaf shape, and the company of minerals such as apophyllite or cavansite. Pink specimens from India's Deccan basalts are the best known.

This information is educational, not buying, selling or investment advice. Value varies enormously with quality and treatment.

## Myths and misconceptions

- Myth: Stilbite's pearly sheen comes from a polish applied to it. Fact: The sheen is natural: stilbite's perfect cleavage faces on {010} shine like pearl. The mineral even takes its name from it, from the Greek for “to shine”.

## Curious questions

**Why does stilbite grow in bow-tie shapes?**

Stilbite's thin, plate-like crystals grow by fanning out from a single centre and leaning against each other. Its groups therefore look like a sheaf of wheat or a bow-tie pinched in the middle; this shape is stilbite's most recognisable feature.

## Did you know?

- In the Deccan basalts near Mumbai and Pune in India, salmon-pink stilbite crystals occur with pale green apophyllite.
- It was once also called desmine, meaning “a bundle”; the name is still used in Germany.
- Its crystals can grow up to 14 cm.

## Where is it found?

- Pune (Poona), Maharashtra, India (Major deposit): The Deccan basalts are the world's most prolific source of stilbite; salmon-pink crystals occur with pale green apophyllite
- Nashik, Maharashtra, India (Known locality): One of the Deccan districts the Handbook of Mineralogy cites for exceptional crystals
- Teigarhorn, near Djúpivogur, Iceland (Known locality): One of the Icelandic localities the Handbook of Mineralogy cites for large, fine crystals (coordinate is Djúpivogur)
- Faroe Islands (Known locality): Stilbite occurs in the basalts of several of the islands

## Sources

- [Stilbite](https://en.wikipedia.org/wiki/Stilbite), Wikipedia
- [Handbook of Mineralogy: Stilbite](https://www.handbookofmineralogy.org/pdfs/stilbite-Ca.pdf), Mineralogical Society of America


Source: https://taslar.bumba.tr/en/stones/stilbite/ · Licence: CC BY-SA 4.0