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?
3-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.
- 2Read the lusterHold the specimen under a strong light. Luster: pearly.
- 3Match the color rangeCompare against the expected color range: white, cream, iridescent, pink, blue.
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
- Luster
- Pearly
- Transparency
- Opaque
- Rarity
- Rare
- Uses
- Gemstone, Collector
- Host rock
- sedimentary layers
Where rockhounds find fire pearl
1 mapped spotsClassic worldwide localities
- Canada
- USA
Field-hunting tip
Where it forms: sedimentary layers. If you start seeing aragonite, calcite in float, you are in the right ground. In the U.S., the densest reported localities are in Texas. Start trip planning there.
Common questions
How do you identify fire pearl?+
Where is fire pearl found?+
Can I find fire pearl in the United States?+
What rocks look like fire pearl?+
What minerals are found with fire pearl?+
What kind of rock does fire pearl form in?+
What is fire pearl used for?+
Find fire pearl on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
