Kladnoite is an extremely rare organic mineral found as sublimation crusts in burning coal mine waste piles. It is highly unstable and water-soluble, requiring careful preservation away from humidity. Collectors prize it for its unique chemical origin as a naturally occurring organic phthalimide derivative.
Is this kladnoite?
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 kladnoite with a known reference. Kladnoite sits at Mohs 1.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Kladnoite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Kladnoite typically shows a dull luster.
- 4Match the color rangeCompare against the expected color range: white, yellowish, brownish.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: sublimation crusts, fine crystalline aggregates.
Often found alongside kladnoite
Minerals reported to co-occur with kladnoite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- C₆H₄(NH)₂CO
- Mohs hardness
- 1.5
- Density
- 1.33 g/cm³
- Streak
- White
- Luster
- Dull
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Sublimation Crusts, Fine Crystalline Aggregates
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Burning Coal Mine Dumps
- Typical price
- $50-300 per specimen
Where rockhounds find kladnoite
Classic worldwide localities
- Kladno coal district, Czech Republic
- Zwickau, Germany
- Donets Basin, Ukraine
Field-hunting tip
Look in burning coal mine dumps country — that is the host setting where kladnoite typically forms. If you start seeing sal-ammoniac, sulfur, boussingaultite in float, you are in the right ground. Field specimens usually show a sublimation crusts, fine crystalline aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find kladnoite on the map
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