Catapleiite typically forms as distinctive pseudohexagonal tabular crystals, often occurring in alkaline igneous environments. It is highly sought after by collectors of micro-minerals for its clean, often glass-like crystal shapes. It is most notably found in the famous nepheline syenite pegmatites of Mont Saint-Hilaire.
Is this catapleiite?
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 catapleiite with a known reference. Catapleiite sits at Mohs 5.5-6 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Catapleiite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Catapleiite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white, yellow, brown, reddish-brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals, pseudohexagonal.
Often confused with
Catapleiite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside catapleiite
Minerals reported to co-occur with catapleiite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₂ZrSi₃O₉·2H₂O
- Mohs hardness
- 5.5-6
- Density
- 2.8 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular Crystals, Pseudohexagonal
- Cleavage
- Good in One Direction
- Rarity
- Uncommon
- Uses
- Collector
- Host rock
- Alkaline Igneous Rocks, Pegmatites
- Typical price
- $10-100 per specimen
Where rockhounds find catapleiite
Classic worldwide localities
- Mont Saint-Hilaire, Quebec, Canada
- Kola Peninsula, Russia
- Langesundsfjord, Norway
- Narssârssuk, Greenland
Field-hunting tip
Look in alkaline igneous rocks, pegmatites country — that is the host setting where catapleiite typically forms. If you start seeing aegirine, microcline, natrolite in float, you are in the right ground. Field specimens usually show a tabular crystals, pseudohexagonal habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find catapleiite on the map
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