Erionite-Na is a rare fibrous zeolite that typically forms delicate, needle-like crystals in volcanic cavities. It is scientifically significant due to its health hazards associated with its asbestiform crystal habit, which is similar to other erionite group minerals.
Is this erionite-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 erionite-na with a known reference. Erionite-Na sits at Mohs 3.5-4, 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 to silky.
- 4Match the color rangeCompare against the expected color range: white, green, gray, orange.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: acicular.
Often confused with
Erionite-Na vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside erionite-na
Minerals reported to co-occur with erionite-na. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₁₀(Si₂₆Al₁₀O₇₂)·30H₂O
- Mohs hardness
- 3.5-4
- Density
- 2.09-2.13 g/cm³
- Streak
- White
- Luster
- Vitreous to silky
- Transparency
- Transparent
- Crystal system
- Hexagonal
- Crystal habit
- Acicular
- Cleavage
- Distinct on {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Occurs in volcanic and sedimentary rocks
Where rockhounds find erionite-na
Classic worldwide localities
- Oregon, USA
- Nevada, USA
- Iceland
- Northern Ireland
- Czech Republic
Field-hunting tip
Where it forms: Occurs in volcanic and sedimentary rocks. If you start seeing phillipsite, chabazite, calcite in float, you are in the right ground. Typical habit: acicular. Train your eye for that shape before scanning the outcrop.






