Garronite-Na is a rare member of the zeolite group typically found as small, radiating clusters of prismatic crystals in vugs within basaltic rocks. It is most easily identified by its characteristic pseudotetragonal habit and association with other zeolites in volcanic settings, though it often requires XRD analysis for definitive verification due to its similarity to gismondine.
Is this garronite-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 garronite-na with a known reference. Garronite-Na sits at Mohs 4.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Garronite-Na leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Garronite-Na typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, yellowish.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: pseudotetragonal prismatic crystals, radiating clusters, crusts.
Often confused with
Garronite-Na vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside garronite-na
Minerals reported to co-occur with garronite-na. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₂Ca₅(Si₁₈Al₁₀)O₅₆·27H₂O
- Mohs hardness
- 4.5
- Density
- 2.12 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Pseudotetragonal Prismatic Crystals, Radiating Clusters, Crusts
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector, Scientific Research
- Host rock
- Basaltic Volcanic Cavities
- Typical price
- $20-100 micro/thumbnail
Where rockhounds find garronite-na
Classic worldwide localities
- Garron Plateau, Northern Ireland
- Mount Adamson, Antarctica
- Cape Grim, Tasmania
Field-hunting tip
Look in basaltic volcanic cavities country — that is the host setting where garronite-na typically forms. If you start seeing phillipsite, chabazite, thomsonite in float, you are in the right ground. Field specimens usually show a pseudotetragonal prismatic crystals, radiating clusters, crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify garronite-na?+
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What rocks look like garronite-na?+
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Find garronite-na on the map
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