Lapearlite is the mineralogical term for the nacreous, calcium carbonate material that forms the layers of pearls and shells. It consists of aragonite crystals arranged in thin, overlapping plates that produce a characteristic iridescent luster. Collectors usually find it as a component of fossilized shells or as organic gem material.
Is this lapearlite?
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 lapearlite with a known reference. Lapearlite sits at Mohs 3.5-4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Lapearlite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Lapearlite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: white, cream, yellowish, colorless.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: nacreous layers.
Often confused with
Lapearlite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside lapearlite
Minerals reported to co-occur with lapearlite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaCO₃
- Mohs hardness
- 3.5-4
- Density
- 2.95 g/cm³
- Streak
- White
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Nacreous Layers
- Cleavage
- Imperfect
- Fluorescence
- Often Fluorescent Under UV
- Rarity
- Common
- Uses
- Decorative, Collector
- Host rock
- Biogenic Deposits
- Typical price
- $5-50 for small specimens
Where rockhounds find lapearlite
2 mapped spotsClassic worldwide localities
- worldwide in marine environments
- freshwater mollusk habitats
Field-hunting tip
Look in biogenic deposits country — that is the host setting where lapearlite typically forms. If you start seeing conchiolin, calcite in float, you are in the right ground. Field specimens usually show a nacreous layers habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Louisiana — start trip planning there.
Common questions
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Find lapearlite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
