Gmelinite-Na is a member of the zeolite group typically found as distinctive rhombohedral crystals lining cavities in basalt. Collectors should look for its characteristic pseudo-hexagonal shape and frequent twinning, often accompanied by other zeolite minerals in volcanic environments.
Is this gmelinite-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 gmelinite-na with a known reference. Gmelinite-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. Gmelinite-Na leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Gmelinite-Na typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, pink, yellow, orange.
- 5Look at form & habitCrystal system: trigonal. Typical habit: rhombohedral crystals, often with curved faces.
Often confused with
Gmelinite-Na vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside gmelinite-na
Minerals reported to co-occur with gmelinite-na. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Na₂,Ca,K₂)₄(Al₈Si₁₆O₄₈)·22H₂O
- Mohs hardness
- 4.5
- Density
- 2.05-2.15 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Trigonal
- Crystal habit
- Rhombohedral Crystals, Often with Curved Faces
- Cleavage
- Distinct On {1011}
- Rarity
- Uncommon
- Uses
- Collector
- Host rock
- Basaltic Vugs and Cavities
- Typical price
- $15-80 thumbnail, $50-200 cabinet specimen
Where rockhounds find gmelinite-na
Classic worldwide localities
- Antrim, Northern Ireland
- Cape Blomidon, Nova Scotia, Canada
- Victoria, Australia
- Table Mountain, Oregon, USA
Field-hunting tip
Look in basaltic vugs and cavities country — that is the host setting where gmelinite-na typically forms. If you start seeing chabazite, natrolite, calcite in float, you are in the right ground. Field specimens usually show a rhombohedral crystals, often with curved faces habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify gmelinite-na?+
Where is gmelinite-na found?+
How much is gmelinite-na worth?+
What rocks look like gmelinite-na?+
What minerals are found with gmelinite-na?+
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Find gmelinite-na on the map
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