Heulandite is a common member of the zeolite group, typically identified by its unique coffin-shaped crystal habit. It is frequently found lining cavities in basaltic rocks, often associated with other zeolites like stilbite or apophyllite.
Is this heulandite?
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 heulandite with a known reference. Heulandite sits at Mohs 3.5-4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Heulandite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Heulandite typically shows a vitreous to pearly luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, yellow, pink, orange, red, brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals often with a coffin-like shape, crusts, radial aggregates.
Often confused with
Heulandite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Luster reads vitreous to pearly on Heulandite and vitreous on Stilbite.
How to tell apart: Luster reads vitreous to pearly on Heulandite and vitreous on Laumontite.
How to tell apart: Luster reads vitreous to pearly on Heulandite and vitreous on Chabazite.
Often found alongside heulandite
Minerals reported to co-occur with heulandite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Ca,Na,K)₅(Si₂₇Al₉)O₇₂·26H₂O
- Mohs hardness
- 3.5-4
- Density
- 2.1-2.2 g/cm³
- Streak
- White
- Luster
- Vitreous to Pearly
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular Crystals Often with A Coffin-like Shape, Crusts, Radial Aggregates
- Cleavage
- Perfect On {010}
- Rarity
- Common
- Uses
- Collector, Geological Study
- Host rock
- Basaltic Vugs, Cavities in Volcanic Rocks
- Typical price
- $10-150 depending on specimen size and clarity
Where rockhounds find heulandite
1 mapped spotsClassic worldwide localities
- India
- Iceland
- USA
- Scotland
- Italy
- Canada
Field-hunting tip
Look in basaltic vugs, cavities in volcanic rocks country — that is the host setting where heulandite typically forms. If you start seeing stilbite, apophyllite, quartz in float, you are in the right ground. Field specimens usually show a tabular crystals often with a coffin-like shape, crusts, radial aggregates habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Oregon — start trip planning there.
Common questions
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Find heulandite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
