Phillipsite-Na is a member of the zeolite group most commonly found in the cavities of volcanic rocks. It is best recognized by its characteristic cruciform twinning, which creates a complex, cross-shaped appearance in crystal clusters.
Is this phillipsite-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 phillipsite-na with a known reference. Phillipsite-Na sits at Mohs 4-4.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Phillipsite-Na leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Phillipsite-Na typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, yellowish, reddish.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: cruciform penetration twins, prismatic.
Often confused with
Phillipsite-Na vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside phillipsite-na
Minerals reported to co-occur with phillipsite-na. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Na,K,Ca)₁.₅(Si,Al)₈O₁₆·6H₂O
- Mohs hardness
- 4-4.5
- Density
- 2.16-2.20 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Cruciform Penetration Twins, Prismatic
- Cleavage
- Distinct On {100} and {010}
- Rarity
- Common
- Uses
- Collector, Geological Study
- Host rock
- Basaltic Volcanic Rocks, Alkaline Igneous Rocks
- Typical price
- $10-60 per specimen
Where rockhounds find phillipsite-na
Classic worldwide localities
- Vesuvius (Italy)
- Iceland
- Germany
- United States
- Hawaii
Field-hunting tip
Look in basaltic volcanic rocks, alkaline igneous rocks country — that is the host setting where phillipsite-na typically forms. If you start seeing calcite, analcime, natrolite in float, you are in the right ground. Field specimens usually show a cruciform penetration twins, prismatic habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify phillipsite-na?+
Where is phillipsite-na found?+
How much is phillipsite-na worth?+
What rocks look like phillipsite-na?+
What minerals are found with phillipsite-na?+
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Find phillipsite-na on the map
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