Picromerite is a water-soluble sulfate mineral often found as an efflorescence in salt deposits or volcanic fumaroles. It typically occurs as white to colorless crusts or small tabular crystals and is prized by mineral collectors of evaporite species.
Is this picromerite?
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 picromerite with a known reference. Picromerite 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. Picromerite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Picromerite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, pale yellow, pale green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals, crusts, efflorescent coatings.
Often confused with
Picromerite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside picromerite
Minerals reported to co-occur with picromerite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- K₂Mg(SO₄)₂·6H₂O
- Mohs hardness
- 2.5
- Density
- 2.15 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular Crystals, Crusts, Efflorescent Coatings
- Cleavage
- Distinct On {010}
- Rarity
- Common
- Uses
- Collector
- Host rock
- Evaporite Deposits, Fumaroles
- Typical price
- $10-40 thumbnail specimen
Where rockhounds find picromerite
Classic worldwide localities
- Vesuvius, Italy
- Kalush, Ukraine
- Stassfurt, Germany
- Carlsbad, New Mexico, USA
Field-hunting tip
Look in evaporite deposits, fumaroles country — that is the host setting where picromerite typically forms. If you start seeing halite, sylvite, kieserite in float, you are in the right ground. Field specimens usually show a tabular crystals, crusts, efflorescent coatings habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify picromerite?+
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How much is picromerite worth?+
What rocks look like picromerite?+
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Find picromerite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
