Fire pearl refers to rare, iridescent organic structures formed within fossilized mollusk shells, particularly those found in the Bearpaw Formation. Collectors seek specimens exhibiting vibrant spectral play-of-color resulting from the preservation of nacreous layers over millions of years. They are typically found as shell fragments and require careful stabilization for display.
Is this fire pearl?
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 fire pearl with a known reference. Fire Pearl sits at Mohs 2.5-4.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Fire Pearl leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Fire Pearl typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: white, cream, iridescent, pink, blue.
- 5Look at form & habitTypical habit: massive.
Often confused with
Fire Pearl vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside fire pearl
Minerals reported to co-occur with fire pearl. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Mohs hardness
- 2.5-4.5
- Density
- 2.6-2.9 g/cm³
- Streak
- White
- Luster
- Pearly
- Transparency
- Opaque
- Crystal habit
- Massive
- Cleavage
- None
- Rarity
- Rare
- Uses
- Gemstone, Collector
- Host rock
- Sedimentary Layers
- Typical price
- $50-500 per specimen
Where rockhounds find fire pearl
1 mapped spotsClassic worldwide localities
- Canada
- USA
Field-hunting tip
Look in sedimentary layers country — that is the host setting where fire pearl typically forms. If you start seeing aragonite, calcite in float, you are in the right ground. Field specimens usually show a massive habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Texas — start trip planning there.
Common questions
How do you identify fire pearl?+
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Find fire pearl on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
