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.

Hardness

3.5-4

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrareZeolite Group family

Erionite-Na

Hardness: 3.5-4
Luster: Vitreous
Streak: White
Transparency: Transparent

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Is this erionite-na?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try 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.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Erionite-Na leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Erionite-Na typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: white, colorless, yellow.
5
Look at form & habit
Crystal system: hexagonal. Typical habit: acicular crystals, fibrous, radiating clusters.

Often confused with

Erionite-Na vs. its common look-alikes — and how to tell them apart in the field.

How to tell apart: Mesolite is the harder of the two (Mohs 5 vs. 3.5-4).

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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: (Na₂,Ca,K₂)₃Al₆Si₂₇O₆₆·27H₂O
Mohs hardness: 3.5-4
Density: 2.05-2.15 g/cm³
Colors: White Colorless Yellow
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Hexagonal
Crystal habit: Acicular Crystals, Fibrous, Radiating Clusters
Cleavage: Distinct
Rarity: Rare
Uses: Collector
Host rock: Volcanic Basalt Cavities
Typical price: $20-150 per specimen

Where rockhounds find erionite-na

Classic worldwide localities

Oregon, USA
Nevada, USA
Iceland
Northern Ireland
Czech Republic

Field-hunting tip

Look in volcanic basalt cavities country — that is the host setting where erionite-na typically forms. If you start seeing phillipsite, chabazite, calcite in float, you are in the right ground. Field specimens usually show a acicular crystals, fibrous, radiating clusters habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify erionite-na?+

Mohs hardness is 3.5-4. It typically shows a vitreous luster. The streak is white. Common colors include white, colorless, yellow.

Where is erionite-na found?+

Notable localities include Oregon, USA; Nevada, USA; Iceland; Northern Ireland; Czech Republic.

How much is erionite-na worth?+

Typical asking prices fall in the range of $20-150 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

Is erionite-na safe to handle?+

It contains toxic constituents. Contains asbestiform fibers that are carcinogenic if inhaled. Handle with extreme caution, store in sealed containers, and avoid creating dust. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like erionite-na?+

Erionite-Na is most often confused with Offretite, Mesolite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with erionite-na?+

Erionite-Na commonly co-occurs with Phillipsite, Chabazite, Calcite, Analcime. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does erionite-na form in?+

Erionite-Na typically forms in volcanic basalt cavities. Working float back to the host body is the standard way to chase a fresh occurrence.

What is erionite-na used for?+

Erionite-Na is used in collector.

Find erionite-na on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.