Natrolite is a widely sought-after zeolite known for its beautiful, delicate needle-like or hair-like crystal sprays. Collectors should look for radiating clusters inside basalt cavities, often associated with other secondary minerals like apophyllite or analcime.
Is this natrolite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch natrolite with a known reference. Natrolite sits at Mohs 5-5.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Natrolite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Natrolite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, gray, yellow, red, pink.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: acicular or fibrous crystals, often as radiating sprays or tufts.
Often confused with
Natrolite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside natrolite
Minerals reported to co-occur with natrolite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₂Al₂Si₃O₁₀·2H₂O
- Mohs hardness
- 5-5.5
- Density
- 2.2-2.3 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Acicular or Fibrous Crystals, Often as Radiating Sprays or Tufts
- Cleavage
- Perfect Prismatic
- Rarity
- Common
- Uses
- Collector, Scientific Study
- Host rock
- Volcanic Rocks, Specifically in Amygdaloidal Cavities of Basalt and Phonolite
- Typical price
- $10-150 depending on specimen size and clarity
Where rockhounds find natrolite
3 mapped spotsClassic worldwide localities
- Mont Saint-Hilaire, Canada
- Khibiny Massif, Russia
- Aussig, Czech Republic
- Faroe Islands
- New Jersey, USA
Field-hunting tip
Look in volcanic rocks, specifically in amygdaloidal cavities of basalt and phonolite country — that is the host setting where natrolite typically forms. If you start seeing analcime, apophyllite, prehnite in float, you are in the right ground. Field specimens usually show a acicular or fibrous crystals, often as radiating sprays or tufts habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Montana, New Jersey, Virginia — start trip planning there.
Common questions
How do you identify natrolite?+
Where is natrolite found?+
Can I find natrolite in the United States?+
How much is natrolite worth?+
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Find natrolite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
