Coralloite is a rare manganese arsenate mineral that forms distinctive, coral-like botryoidal aggregates. It is primarily found in specialized hydrothermal environments rich in manganese and arsenic, often associated with secondary manganese minerals.
Is this coralloite?
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 coralloite with a known reference. Coralloite sits at Mohs 3-4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Coralloite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Coralloite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: white, pale pink.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: botryoidal, crusts, radial aggregates.
Often confused with
Coralloite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Coralloite leaves white, Arthurite leaves pale green; luster reads pearly on Coralloite and vitreous on Arthurite.
How to tell apart: Luster reads pearly on Coralloite and adamantine on Pharmacosiderite.
Often found alongside coralloite
Minerals reported to co-occur with coralloite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mn²⁺Mg₂(AsO₄)₂·8H₂O
- Mohs hardness
- 3-4
- Density
- 2.5 g/cm³
- Streak
- White
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Botryoidal, Crusts, Radial Aggregates
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Veins
- Typical price
- $50-300 per specimen
Where rockhounds find coralloite
Classic worldwide localities
- Jianshan mine, Mangshi, China
Field-hunting tip
Look in hydrothermal veins country — that is the host setting where coralloite typically forms. If you start seeing manganoan calcite, rhodochrosite, arsenopyrite in float, you are in the right ground. Field specimens usually show a botryoidal, crusts, radial aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find coralloite on the map
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