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.

Hardness

3.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrare

Vauxite

Hardness: 3.5
Luster: Vitreous
Streak: White
Transparency: Translucent

Is this vauxite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch vauxite with a known reference. Vauxite sits at Mohs 3.5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Vauxite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Vauxite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: sky blue, blue-green.
5
Look at form & habit
Crystal system: triclinic. Typical habit: radiating globular aggregates, crusts, or small prismatic crystals.

Often confused with

Vauxite vs. its common look-alikes, and how to tell them apart in the field.

mineral

Vivianite

Mohs 1.5-2

How to tell apart: Vauxite is noticeably harder (Mohs 3.5 vs. 1.5-2); streak differs, so Vauxite leaves white, Vivianite leaves white to light blue.

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: 2.44 g/cm³
Colors: Sky Blue Blue-green
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Triclinic
Crystal habit: Radiating Globular Aggregates, Crusts, Or Small Prismatic Crystals
Cleavage: Perfect On {010}
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Tin Veins in Altered Dacite Porphyry
Typical price: $50-500 depending on specimen size and clarity

Where rockhounds find vauxite

Classic worldwide localities

Siglo XX Mine, Llallagua, Bolivia

Field-hunting tip

Look in hydrothermal tin veins in altered dacite porphyry country, the host setting where vauxite typically forms. If you start seeing paravauxite, metavauxite, childrenite in float, you are in the right ground. Field specimens usually show a radiating globular aggregates, crusts, or small prismatic crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify vauxite?+

Mohs hardness is 3.5. It typically shows a vitreous luster. The streak is white. Common colors include sky blue, blue-green.

Where is vauxite found?+

Notable localities include Siglo XX Mine, Llallagua, Bolivia.

How much is vauxite worth?+

Typical asking prices fall in the range of $50-500 depending on specimen size and clarity. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like vauxite?+

Vauxite is most often confused with Vivianite, Paravauxite, Metavauxite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with vauxite?+

Vauxite commonly co-occurs with Paravauxite, Metavauxite, Childrenite, Vivianite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does vauxite form in?+

Vauxite typically forms in hydrothermal tin veins in altered dacite porphyry. Working float back to the host body is the standard way to chase a fresh occurrence.

What is vauxite used for?+

Vauxite is used in collector.

Find vauxite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.