Szomolnokite is a secondary sulfate mineral that typically forms as efflorescent crusts or granular aggregates in the oxidation zones of iron-bearing sulfide deposits. It is often pale yellow or brownish in color and is notorious for being unstable in humid environments, where it may hydrate into other iron sulfate species. Collectors should store this mineral in a dry, sealed container to prevent degradation.
Is this szomolnokite?
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 szomolnokite with a known reference. Szomolnokite 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. Szomolnokite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Szomolnokite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, yellow-white, brownish-white.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: crusts, granular, fibrous.
Often confused with
Szomolnokite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside szomolnokite
Minerals reported to co-occur with szomolnokite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- FeSO₄·H₂O
- Mohs hardness
- 2.5
- Density
- 3.07 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Crusts, Granular, Fibrous
- Cleavage
- Perfect
- Rarity
- Uncommon
- Uses
- Collector, Scientific Reference
- Host rock
- Oxidized Zones of Sulfide Ore Deposits
- Typical price
- $15-60 for small specimens
Where rockhounds find szomolnokite
Classic worldwide localities
- Szomolnok, Slovakia
- Rio Tinto, Spain
- Chuquicamata, Chile
- Bisbee, Arizona, USA
Field-hunting tip
Look in oxidized zones of sulfide ore deposits country — that is the host setting where szomolnokite typically forms. If you start seeing melanterite, chalcanthite, pyrite in float, you are in the right ground. Field specimens usually show a crusts, granular, fibrous habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find szomolnokite on the map
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