Cuprocopiapite is a rare copper-bearing member of the copiapite group formed by the oxidation of iron and copper sulfide minerals. It typically presents as yellow to greenish-yellow crusts or small, platy crystal aggregates in arid mining environments. Collectors should be aware that like other hydrous sulfates, it is water-soluble and should be stored in a dry environment.
Is this cuprocopiapite?
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 cuprocopiapite with a known reference. Cuprocopiapite sits at Mohs 2.5-3 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Cuprocopiapite leaves a yellow streak.
- 3Read the lusterHold the specimen under a strong light. Cuprocopiapite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: yellow, greenish-yellow.
- 5Look at form & habitCrystal system: triclinic. Typical habit: platy crystals, granular crusts, powdery efflorescences.
Often confused with
Cuprocopiapite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Cuprocopiapite leaves yellow, Fibroferrite leaves white; luster reads pearly on Cuprocopiapite and silky on Fibroferrite.
How to tell apart: Streak differs — Cuprocopiapite leaves yellow, Halotrichite leaves white; luster reads pearly on Cuprocopiapite and vitreous on Halotrichite.
Often found alongside cuprocopiapite
Minerals reported to co-occur with cuprocopiapite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CuFe₄(SO₄)₆(OH)₂·20H₂O
- Mohs hardness
- 2.5-3
- Density
- 2.1-2.2 g/cm³
- Colors
- Streak
- Yellow
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Triclinic
- Crystal habit
- Platy Crystals, Granular Crusts, Powdery Efflorescences
- Cleavage
- Perfect On {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zones of Copper-rich Sulfide Deposits
- Typical price
- $20-150 for micro-mounts or small specimens
Where rockhounds find cuprocopiapite
Classic worldwide localities
- Chuquicamata, Chile
- Rio Tinto, Spain
- United Verde Mine, USA
- Alum Cave, USA
Field-hunting tip
Look in oxidized zones of copper-rich sulfide deposits country — that is the host setting where cuprocopiapite typically forms. If you start seeing copiapite, jarosite, melanterite in float, you are in the right ground. Field specimens usually show a platy crystals, granular crusts, powdery efflorescences habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify cuprocopiapite?+
Where is cuprocopiapite found?+
How much is cuprocopiapite worth?+
What rocks look like cuprocopiapite?+
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Find cuprocopiapite on the map
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