Mansfieldite is an uncommon hydrated aluminum arsenate mineral often occurring as a secondary mineral in oxidized ore zones. It is typically found as small, crusty, or radial aggregates and is structurally related to variscite. Because it contains arsenic, it should be handled with care by collectors.
Is this mansfieldite?
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 mansfieldite with a known reference. Mansfieldite sits at Mohs 3.5-4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Mansfieldite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Mansfieldite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, pale yellow.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: crusts, aggregates of minute crystals, radial groups.
Often confused with
Mansfieldite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside mansfieldite
Minerals reported to co-occur with mansfieldite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- AlAsO₄·2H₂O
- Mohs hardness
- 3.5-4
- Density
- 2.83 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Crusts, Aggregates of Minute Crystals, Radial Groups
- Cleavage
- Distinct
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zones of Arsenic-rich Mineral Deposits
- Typical price
- $20-150 for small specimens
Where rockhounds find mansfieldite
Classic worldwide localities
- Mansfield, Indiana, USA
- Jachymov, Czech Republic
- Schneeberg, Germany
Field-hunting tip
Look in oxidized zones of arsenic-rich mineral deposits country — that is the host setting where mansfieldite typically forms. If you start seeing scorodite, arsenopyrite, limonite in float, you are in the right ground. Field specimens usually show a crusts, aggregates of minute crystals, radial groups habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find mansfieldite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
