Mazzite-Mg is a rare zeolite mineral that forms distinctive hexagonal prismatic crystals in volcanic cavities. It is most frequently found lining vesicles in alkaline basalt, often occurring in complex intergrowths with other zeolite minerals.
Is this mazzite-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 mazzite-mg with a known reference. Mazzite-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: vitreous.
- 4Match the color rangeCompare against the expected color range: white, colorless.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: acicular, prismatic, radial.
Often confused with
Mazzite-Mg vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside mazzite-mg
Minerals reported to co-occur with mazzite-mg. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mg₅(Si₂₆Al₁₀)O₇₂·30H₂O
- Mohs hardness
- 4
- Density
- 2.108 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Hexagonal
- Crystal habit
- Acicular, prismatic, radial
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In cavities in a porphyritic olivine basalt
Where rockhounds find mazzite-mg
Classic worldwide localities
- Mont Sémiol (Mont Semiouse), near Montbrison, Loire, France
Field-hunting tip
Where it forms: In cavities in a porphyritic olivine basalt. If you start seeing phillipsite, offretite, chabazite in float, you are in the right ground. Typical habit: acicular, prismatic, radial. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify mazzite-mg?+
Where is mazzite-mg found?+
What rocks look like mazzite-mg?+
What minerals are found with mazzite-mg?+
What kind of rock does mazzite-mg form in?+
What is mazzite-mg used for?+
Find mazzite-mg on the map
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