RocksdayNatrolite vs Scolecite
How to tell them apart
A zeolite forming glassy, needle-like crystals in sprays.
Photo: Didier Descouens, CC BY-SA 4.0
A zeolite forming sprays of slender, glassy white needles.
Photo: Carles Millan, CC BY 3.0
Key differences
- Scolecite looks very similar; a lab is usually needed.
- Natrolite looks almost identical; usually only lab tests separate them.
Side by side
| Property | Natrolite | Scolecite |
|---|---|---|
| Type | Mineral | Mineral |
| Mohs hardness | 5–5.5 | 5–5.5 |
| Luster | Vitreous to silky | Vitreous to silky |
| Streak | White | White |
| Colors | White, Clear | White, Clear |
| Crystal system | Orthorhombic | Monoclinic |
| Specific gravity | 2.2–2.26 | 2.25–2.29 |
| Formula | Na₂Al₂Si₃O₁₀·2H₂O | CaAl₂Si₃O₁₀·3H₂O |
| Found in | New Jersey; Kola Peninsula, Russia | Pune, India; Iceland |
Properties that are the same for both are grayed out.
How to identify natrolite
- Clear to white needles in radiating sprays.
- Square cross-section on larger crystals.
- Light and brittle.
Crystal system: Orthorhombic
Full Natrolite guide →How to identify scolecite
- Radiating sprays of thin, straight white needles.
- Often with apophyllite or stilbite.
- Brittle needles snap easily.
Crystal system: Monoclinic
Full Scolecite guide →More comparisons
Could you tell them apart from a blurry close-up?
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