Specimen at a glance
| Mineral | Stilbite (zeolite group) |
|---|---|
| Chemistry | NaCa4(Si27Al9)O72·28H2O |
| Mohs hardness | 3.5–4 |
| Crystal system | Monoclinic |
| Locality | New Jersey |
| Form | Lot / parcel |
| You receive | The exact lot pictured |
About this specimen
Stilbite is a zeolite — a family of hydrated aluminosilicate minerals that form in gas cavities (vesicles) left behind in cooling volcanic rock, precipitated later by mineral-rich water moving through the stone. Its crystals typically grow in sheaf-like or radiating bundles that fan out into the classic “bowtie” shape seen in this lot, and the warm peachy-orange color is typical of New Jersey material, usually from iron staining absorbed during formation.
New Jersey’s basalt (trap-rock) quarries around Paterson, Great Notch, and the Watchung Mountains are among the most famous zeolite localities in the world, mined for both stone and minerals since the 1800s and still turning up stilbite, prehnite, and related species today. Stilbite rates a soft 3.5–4 on the Mohs scale, so it should be handled more gently than quartz — avoid dropping it or scrubbing it, and clean with a soft dry brush or cloth only.
This lot of nine specimens includes one notably larger piece alongside eight smaller bowtie clusters, making it a solid value lot for zeolite collectors or for anyone reselling specimens individually.
Inside Stilbite
Look for the bowtie — it’s one of the easiest twinned crystals to spot with the naked eye.
The story: Zeolites like stilbite are among the last minerals to crystallize inside a cooling lava flow, forming in the gas bubbles (vesicles) left behind as the rock solidified. Stilbite typically grows as twinned, sheaf-shaped crystals that fan out from a shared point — the classic ‘bowtie’ every New Jersey trap-rock collector learns to recognize on sight.
Why collectors chase it: The bowtie twinning is crystallography you can see without a loupe, and the pearly luster on its cleavage faces catches light in a way few other minerals do.
Care: Softer than quartz and cleaves easily — support pieces by their matrix rather than gripping the crystal sheaves, and avoid drops.
Stilbite: the science
- Its classic “bowtie” or sheaf habit is made of many thin crystals fanning out from a pinched center.
- The name “zeolite” means boiling stone. When Axel Cronstedt heated stilbite in 1756, the water trapped inside made it froth.
- Zeolites act as molecular sieves and are used industrially to filter gases, soften water, and even capture radioactive cesium.
Go deeper
Want the full story on stilbite: how it forms, how to identify it, and what makes a great specimen?
Read Stilbite & Zeolites: The Complete Guide Shop all Stilbite
Questions about this piece
What is stilbite?
Stilbite is a zeolite, a mineral with open, cage-like channels built into its structure that hold loosely bound water. It grows in gas cavities in basalt and in hydrothermal veins.
Where was it found?
This lot comes from New Jersey. We list a locality whenever it is known, because where a mineral formed is part of its story and its value.
How hard is it, and how should I care for it?
It rates 3.5–4 on the Mohs scale. Mohs 3.5–4 and fragile at the edges. Keep dry, dust with a soft brush or compressed air, and avoid heat, which drives off its water.
Is this the exact lot I will receive?
Yes. This lot was photographed as a group, and you receive the pieces shown.
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