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, 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
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Find fire pearl on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
