Syngenite is a rare potassium-calcium sulfate typically found as a secondary mineral in potash evaporite deposits. Collectors often look for it as delicate prismatic crystals or white crusts associated with salt minerals, requiring careful handling due to its solubility in water.
Is this syngenite?
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 syngenite with a known reference. Syngenite 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. Syngenite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Syngenite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white, pale yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals, tabular, massive, crusts.
Often confused with
Syngenite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside syngenite
Minerals reported to co-occur with syngenite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- K₂Ca(SO₄)₂·H₂O
- Mohs hardness
- 2.5
- Density
- 2.59 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic Crystals, Tabular, Massive, Crusts
- Cleavage
- Perfect On {010}
- Rarity
- Uncommon
- Uses
- Collector, Scientific Research
- Host rock
- Evaporite Deposits, Volcanic Fumaroles
- Typical price
- $10-60 per specimen
Where rockhounds find syngenite
Classic worldwide localities
- Kalusz, Ukraine
- Stassfurt, Germany
- Carlsbad, New Mexico, USA
- Vesuvius, Italy
Field-hunting tip
Look in evaporite deposits, volcanic fumaroles country — that is the host setting where syngenite typically forms. If you start seeing halite, sylvite, kieserite in float, you are in the right ground. Field specimens usually show a prismatic crystals, tabular, massive, crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find syngenite on the map
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