Simonkolleite is a rare secondary zinc mineral often found in the weathered slag of ancient smelting sites or oxidized ore deposits. It typically forms attractive, pearly white to colorless hexagonal plates or rosettes, making it a prized micro-mineral for collectors.
Is this simonkolleite?
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 simonkolleite with a known reference. Simonkolleite 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. Simonkolleite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Simonkolleite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, pale gray, pale green.
- 5Look at form & habitCrystal system: trigonal. Typical habit: platy crystals, tabular, crusts, rosettes.
Often confused with
Simonkolleite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Luster reads pearly on Simonkolleite and dull on Hydrozincite.
How to tell apart: Smithsonite is the harder of the two (Mohs 4-4.5 vs. 2.5); luster reads pearly on Simonkolleite and vitreous on Smithsonite.
How to tell apart: Hemimorphite is the harder of the two (Mohs 4.5-5 vs. 2.5); luster reads pearly on Simonkolleite and vitreous on Hemimorphite.
Often found alongside simonkolleite
Minerals reported to co-occur with simonkolleite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Zn₅(OH)₈Cl₂·H₂O
- Mohs hardness
- 2.5
- Density
- 3.37 g/cm³
- Streak
- White
- Luster
- Pearly
- Transparency
- Transparent
- Crystal system
- Trigonal
- Crystal habit
- Platy Crystals, Tabular, Crusts, Rosettes
- Cleavage
- Perfect On {0001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zinc Ore Deposits, Often in Slag or Tailings
- Typical price
- $20-150 per specimen
Where rockhounds find simonkolleite
Classic worldwide localities
- Lavrion, Greece
- Reichenbach, Germany
- Sterling Hill, New Jersey, USA
Field-hunting tip
Look in oxidized zinc ore deposits, often in slag or tailings country — that is the host setting where simonkolleite typically forms. If you start seeing smithsonite, hydrozincite, hemimorphite in float, you are in the right ground. Field specimens usually show a platy crystals, tabular, crusts, rosettes habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find simonkolleite on the map
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