Direnzoite is an extremely rare member of the zeolite group found in specific volcanic environments. It typically occurs as small tabular crystals associated with other zeolites and calcite in vesicle-filled cavities.
Is this direnzoite?
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 direnzoite with a known reference. Direnzoite sits at Mohs 3.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Direnzoite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Direnzoite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: tabular crystals.
Often confused with
Direnzoite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside direnzoite
Minerals reported to co-occur with direnzoite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₄K₄Ca₂Si₂₀Al₈O₅₆·14H₂O
- Mohs hardness
- 3.5
- Density
- 2.16 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Tabular Crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Volcanic Rocks
- Typical price
- $50-300 per specimen
Where rockhounds find direnzoite
Classic worldwide localities
- Italy
Field-hunting tip
Look in volcanic rocks country — that is the host setting where direnzoite typically forms. If you start seeing calcite, phillipsite, chabazite in float, you are in the right ground. Field specimens usually show a tabular crystals habit, so train your eye for that shape before scanning the outcrop.




