Magnesiocopiapite is a secondary sulfate mineral that typically forms as an efflorescent crust or thin coating in the weathering zones of sulfide deposits. It is best identified by its bright yellow color and occurrence alongside other iron-sulfates; it is highly water-soluble and should be kept dry.
Is this magnesiocopiapite?
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 magnesiocopiapite with a known reference. Magnesiocopiapite 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. Magnesiocopiapite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Magnesiocopiapite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: yellow, golden yellow.
- 5Look at form & habitCrystal system: triclinic. Typical habit: platy crystals, granular crusts, efflorescent aggregates.
Often confused with
Magnesiocopiapite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside magnesiocopiapite
Minerals reported to co-occur with magnesiocopiapite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- MgFe₄³⁺(SO₄)₆(OH)₂·20H₂O
- Mohs hardness
- 2.5-3
- Density
- 2.1-2.2 g/cm³
- Colors
- Streak
- White
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Triclinic
- Crystal habit
- Platy Crystals, Granular Crusts, Efflorescent Aggregates
- Cleavage
- Perfect On {010}
- Rarity
- Uncommon
- Uses
- Collector
- Host rock
- Oxidized Zones of Pyrite-bearing Ore Deposits
- Typical price
- $10-50 for small specimens
Where rockhounds find magnesiocopiapite
Classic worldwide localities
- Chile
- United States
- Germany
- Spain
- Italy
Field-hunting tip
Look in oxidized zones of pyrite-bearing ore deposits country — that is the host setting where magnesiocopiapite typically forms. If you start seeing pyrite, jarosite, melanterite in float, you are in the right ground. Field specimens usually show a platy crystals, granular crusts, efflorescent aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify magnesiocopiapite?+
Where is magnesiocopiapite found?+
How much is magnesiocopiapite worth?+
What rocks look like magnesiocopiapite?+
What minerals are found with magnesiocopiapite?+
What kind of rock does magnesiocopiapite form in?+
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Find magnesiocopiapite on the map
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