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.

Hardness

3-3.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Semitransparent

mineralrare

Poitevinite

Hardness: 3-3.5
Luster: Vitreous
Streak: White
Transparency: Semitransparent

Is this poitevinite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch poitevinite with a known reference. Poitevinite sits at Mohs 3-3.5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: pink, light red.
5
Look at form & habit
Crystal system: triclinic. Typical habit: powdery.

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: CuSO₄·H₂O
Mohs hardness: 3-3.5
Density: 3.30 g/cm³
Colors: Pink Light red
Streak: White
Luster: Vitreous
Transparency: Semitransparent
Crystal system: Triclinic
Crystal habit: Powdery
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: A rare secondary mineral in the oxidized zone of a base-metal hydrothermal mineral prospect

Where rockhounds find poitevinite

Classic worldwide localities

Avoca claim, Hat Creek, Bonaparte River area, Lillooet district, British Columbia, Canada

Field-hunting tip

Where it forms: A rare secondary mineral in the oxidized zone of a base-metal hydrothermal mineral prospect. If you start seeing quartz, gypsum, pyrite in float, you are in the right ground. Typical habit: powdery. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify poitevinite?+

Mohs hardness is 3-3.5. Luster: vitreous. The streak is white. Common colors include pink, light red.

Where is poitevinite found?+

Notable localities include Avoca claim, Hat Creek, Bonaparte River area, Lillooet district, British Columbia, Canada.

Is poitevinite safe to handle?+

Poitevinite contains copper. Wash your hands afterwards, never grind or breathe the dust, and store it apart from specimens you handle often.

What rocks look like poitevinite?+

Poitevinite is most often confused with Szomolnokite, Chalcanthite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with poitevinite?+

Poitevinite commonly co-occurs with Quartz, Gypsum, Pyrite, Bonattite, Scorodite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does poitevinite form in?+

Where it forms: A rare secondary mineral in the oxidized zone of a base-metal hydrothermal mineral prospect. Working float back to the host body is the standard way to chase a fresh occurrence.

What is poitevinite used for?+

Poitevinite is used in collector.

Find poitevinite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.