Poitevinite is a rare copper iron sulfate that typically forms as a secondary mineral in the oxidized zones of copper deposits. It is most often found as efflorescent crusts or small crystalline coatings rather than large crystals, making it a challenging and prized specimen for collectors of rare sulfates.
Is this poitevinite?
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 poitevinite with a known reference. Poitevinite sits at Mohs 2-3 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Poitevinite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Poitevinite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, yellowish-white, pale yellow.
- 5Look at form & habitCrystal system: triclinic. Typical habit: crusts, efflorescent aggregates, coatings.
Often confused with
Poitevinite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside poitevinite
Minerals reported to co-occur with poitevinite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Cu,Fe)SO₄·H₂O
- Mohs hardness
- 2-3
- Density
- 2.74 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Triclinic
- Crystal habit
- Crusts, Efflorescent Aggregates, Coatings
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zones of Copper Ore Deposits
- Typical price
- $20-100 for small specimen fragments
Where rockhounds find poitevinite
Classic worldwide localities
- Chuquicamata, Chile
- Sierra Gorda, Chile
- Bingham Canyon, USA
Field-hunting tip
Look in oxidized zones of copper ore deposits country — that is the host setting where poitevinite typically forms. If you start seeing chalcanthite, brochantite, copiapite in float, you are in the right ground. Field specimens usually show a crusts, efflorescent aggregates, coatings habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find poitevinite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
