Pollucite is a rare zeolite mineral that serves as the primary ore for the element cesium. It most commonly occurs in highly evolved granite pegmatites, often forming complex trapezohedral crystals or appearing as massive, quartz-like white clumps embedded in a matrix of lepidolite and spodumene.
Is this pollucite?
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 pollucite with a known reference. Pollucite sits at Mohs 6.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Pollucite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Pollucite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white, gray, pink, blue.
- 5Look at form & habitCrystal system: isometric. Typical habit: trapezohedral crystals, massive, granular.
Often confused with
Pollucite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside pollucite
Minerals reported to co-occur with pollucite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Cs,Na)₂Al₂Si₄O₁₂·nH₂O
- Mohs hardness
- 6.5
- Density
- 2.86-2.90 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Isometric
- Crystal habit
- Trapezohedral Crystals, Massive, Granular
- Cleavage
- Poor
- Rarity
- Uncommon
- Uses
- Collector, Cesium Ore
- Host rock
- Granite Pegmatites
- Typical price
- $20-150 for small specimens, high-quality crystals can reach $500+
Where rockhounds find pollucite
1 mapped spotsClassic worldwide localities
- Tanco Mine, Canada
- Elba, Italy
- Karibib, Namibia
- Maine, USA
- Nuristan, Afghanistan
Field-hunting tip
Look in granite pegmatites country — that is the host setting where pollucite typically forms. If you start seeing quartz, spodumene, lepidolite in float, you are in the right ground. Field specimens usually show a trapezohedral crystals, massive, granular habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Connecticut — start trip planning there.
Common questions
How do you identify pollucite?+
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Can I find pollucite in the United States?+
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Find pollucite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
