Nacrite is a relatively uncommon member of the kaolinite group, distinguished by its pearly luster and micaceous habit. It is often found in hydrothermal veins and sedimentary deposits where it forms delicate, platy crystals that are visually similar to other clay minerals but can be differentiated by precise mineralogical analysis.
Is this nacrite?
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 nacrite with a known reference. Nacrite sits at Mohs 2.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Nacrite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Nacrite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: white, yellowish, greenish.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: platy or micaceous aggregates, massive.
Often confused with
Nacrite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside nacrite
Minerals reported to co-occur with nacrite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Al₂Si₂O₅(OH)₄
- Mohs hardness
- 2.5
- Density
- 2.6 g/cm³
- Streak
- White
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Platy or Micaceous Aggregates, Massive
- Cleavage
- Perfect Basal
- Rarity
- Uncommon
- Uses
- Collector, Industrial
- Host rock
- Hydrothermal Veins and Low-temperature Metamorphic Environments
- Typical price
- $10-60 per specimen
Where rockhounds find nacrite
Classic worldwide localities
- Brand, Saxony, Germany
- Anglesey, Wales, UK
- Franklin, New Jersey, USA
- Saint-Yrieix, France
Field-hunting tip
Look in hydrothermal veins and low-temperature metamorphic environments country — that is the host setting where nacrite typically forms. If you start seeing quartz, calcite, dolomite in float, you are in the right ground. Field specimens usually show a platy or micaceous aggregates, massive habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find nacrite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
