Vauxite is a rare phosphate mineral prized by collectors for its stunning sky-blue color and delicate radiating crystal sprays. It is almost exclusively found in the Siglo XX mine in Bolivia, where it forms in hydrothermal tin deposits.
Is this vauxite?
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 vauxite with a known reference. Vauxite sits at Mohs 3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: sky blue, dark blue.
- 5Look at form & habitCrystal system: triclinic. Typical habit: aggregates, radial, tabular.
Often confused with
Vauxite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside vauxite
Minerals reported to co-occur with vauxite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Fe²⁺Al₂(PO₄)₂(OH)₂·6H₂O
- Mohs hardness
- 3.5
- Density
- 2.39-2.40 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Triclinic
- Crystal habit
- Aggregates, radial, tabular
- Cleavage
- None
- Fluorescence
- Fluorescent
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A secondary mineral derived from alteration of apatite
Where rockhounds find vauxite
Classic worldwide localities
- Siglo XX mine, Llallagua, Potosí, and at Huanuni, Oruro, Bolivia
Field-hunting tip
Where it forms: A secondary mineral derived from alteration of apatite. If you start seeing wavellite, paravauxite, marcasite in float, you are in the right ground. Typical habit: aggregates, radial, tabular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify vauxite?+
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What rocks look like vauxite?+
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Find vauxite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
