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, 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.
