Heulandite-Na is a common member of the zeolite group often recognized by its distinct coffin-shaped crystal habit. Collectors prize it for its excellent association with other zeolites in basaltic vugs, typically forming clusters of tabular, pearly-lustered crystals.
Is this heulandite-na?
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-na with a known reference. Heulandite-Na sits at Mohs 3-3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to pearly.
- 4Match the color rangeCompare against the expected color range: white, reddish white, grayish white, brownish white, yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: crystalline, tabular.
Often confused with
Heulandite-Na vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside heulandite-na
Minerals reported to co-occur with heulandite-na. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Na,Ca,K)₆(Si,Al)₃₆O₇₂·22H₂O
- Mohs hardness
- 3-3.5
- Density
- 2.2 g/cm³
- Streak
- White
- Luster
- Vitreous to pearly
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Crystalline, tabular
- Cleavage
- Perfect on {010}
- Rarity
- Common
- Uses
- Collector
- Host rock
- Low temperature zeolite found in a wide variety of geologic environments: volcanic rocks, metamorphic rocks, pegmatites, tuffs, and deep-sea sediments
Where rockhounds find heulandite-na
Classic worldwide localities
- Challis, Custer County, Idaho, U.S.A (type locality)
Field-hunting tip
Where it forms: Low temperature zeolite found in a wide variety of geologic environments: volcanic rocks, metamorphic rocks, pegmatites, tuffs, and deep-sea sediments. If you start seeing quartz, apophyllite, calcite in float, you are in the right ground. Typical habit: crystalline, tabular. Train your eye for that shape before scanning the outcrop.
More heulandite-na photos
Common questions
How do you identify heulandite-na?+
Where is heulandite-na found?+
What rocks look like heulandite-na?+
What minerals are found with heulandite-na?+
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Find heulandite-na on the map
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