Dickite is a polymorph of kaolinite and is often found as a white, fine-grained, clay-like material or as distinct, platy micro-crystals. Collectors often find it in hydrothermal veins associated with metallic ores or as a constituent of sedimentary clay beds. It is best identified through X-ray diffraction, as it is visually indistinguishable from other clay minerals to the naked eye.
Is this dickite?
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 dickite with a known reference. Dickite sits at Mohs 2 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Dickite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Dickite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: white, yellowish, brownish.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: platy crystals, compact masses, clay-like.
Often confused with
Dickite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside dickite
Minerals reported to co-occur with dickite. 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
- Density
- 2.6 g/cm³
- Streak
- White
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Platy Crystals, Compact Masses, Clay-like
- Cleavage
- Perfect Basal
- Rarity
- Common
- Uses
- Collector, Industrial
- Host rock
- Hydrothermal Veins, Sedimentary Clay Deposits
- Typical price
- $10-50 per specimen
Where rockhounds find dickite
2 mapped spotsClassic worldwide localities
- Anglesey, Wales
- Pennsylvania, USA
- Pribram, Czech Republic
- Schneeberg, Germany
Field-hunting tip
Look in hydrothermal veins, sedimentary clay deposits country — that is the host setting where dickite typically forms. If you start seeing quartz, pyrite, calcite in float, you are in the right ground. Field specimens usually show a platy crystals, compact masses, clay-like habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Missouri, Wisconsin — start trip planning there.
Common questions
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Find dickite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
