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, 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
How do you identify poitevinite?+
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Find poitevinite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
