Chabazite-Mg is a rare magnesium-dominant member of the zeolite group, often occurring in basaltic vugs. Collectors identify it by its characteristic rhombohedral crystals, which frequently resemble cubes. It is most commonly found in association with other zeolite minerals in volcanic rock cavities.
Is this chabazite-mg?
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 chabazite-mg with a known reference. Chabazite-Mg sits at Mohs ~4, 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: strongly vitreous.
- 4Match the color rangeCompare against the expected color range: colorless.
- 5Look at form & habitCrystal system: trigonal. Typical habit: rhombohedral crystals.
Often confused with
Chabazite-Mg vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads strongly vitreous on Chabazite-Mg and vitreous on Chabazite-Ca.
How to tell apart: Luster reads strongly vitreous on Chabazite-Mg and vitreous on Chabazite-Na.
How to tell apart: Luster reads strongly vitreous on Chabazite-Mg and vitreous on Phillipsite.
Often found alongside chabazite-mg
Minerals reported to co-occur with chabazite-mg. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Mg,Ca,Na₂,K₂)₂Al₄Si₈O₂₄·10H₂O
- Mohs hardness
- ~4
- Density
- 1.98 g/cm³
- Colors
- Streak
- White
- Luster
- Strongly vitreous
- Transparency
- Transparent
- Crystal system
- Trigonal
- Crystal habit
- Rhombohedral crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In cavities in basalt, formed by hydrothermal alteration of feldspar and volcanic glass in a closed system with Mg-rich solutions
Where rockhounds find chabazite-mg
Classic worldwide localities
- Karikás-tető area of Prága Hill, Veszprém County, Balaton Highland, Transdanubia, western Hungary
- Ugione Valley, Monti Livornesi, Livorno, Tuscany, Italy
Field-hunting tip
Where it forms: In cavities in basalt, formed by hydrothermal alteration of feldspar and volcanic glass in a closed system with Mg-rich solutions. If you start seeing saponite, aragonite, phillipsite in float, you are in the right ground. Typical habit: rhombohedral crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify chabazite-mg?+
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What rocks look like chabazite-mg?+
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Find chabazite-mg on the map
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