Mallardite is a rare manganese sulfate mineral that typically forms as delicate, fibrous efflorescences or crusts in mine workings. Because it is highly soluble in water and prone to dehydration, it is difficult to preserve and requires storage in a controlled, dry environment.
Is this mallardite?
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 mallardite with a known reference. Mallardite sits at Mohs 2 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Mallardite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Mallardite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white, yellowish.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: fibrous, acicular, efflorescent.
Often confused with
Mallardite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside mallardite
Minerals reported to co-occur with mallardite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- MnSO₄·7H₂O
- Mohs hardness
- 2
- Density
- 2.05 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Fibrous, Acicular, Efflorescent
- Cleavage
- Distinct
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Manganese-bearing Hydrothermal Deposits
- Typical price
- $20-100 for small study specimens
Where rockhounds find mallardite
Classic worldwide localities
- Lucky C Mine, Utah, USA
- Schellgaden, Austria
- Chvaletice, Czech Republic
Field-hunting tip
Look in oxidized manganese-bearing hydrothermal deposits country — that is the host setting where mallardite typically forms. If you start seeing melanterite, szomolnokite, pyrite in float, you are in the right ground. Field specimens usually show a fibrous, acicular, efflorescent habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find mallardite on the map
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