Gibbsite is a primary mineral component of bauxite and typically appears in white, waxy, or pearly tabular crystals or botryoidal masses. It is commonly found in tropical weathering zones or as a secondary mineral in hydrothermal alteration environments.

Hardness

2.5-3.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralcommon

Gibbsite

Hardness: 2.5-3.5
Luster: Vitreous
Streak: White
Transparency: Translucent

Is this gibbsite?

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 gibbsite with a known reference. Gibbsite sits at Mohs 2.5-3.5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Gibbsite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Gibbsite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: white, grayish-white, yellowish, reddish-white.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: tabular crystals, massive, botryoidal, stalactitic.

Often confused with

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

How to tell apart: Luster reads vitreous on Gibbsite and dull on Kaolinite.

How to tell apart: Diaspore is the harder of the two (Mohs 6.5-7 vs. 2.5-3.5).

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Often found alongside gibbsite

Minerals reported to co-occur with gibbsite. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula: Al(OH)₃
Mohs hardness: 2.5-3.5
Density: 2.4 g/cm³
Colors: White Grayish-white Yellowish Reddish-white
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Tabular Crystals, Massive, Botryoidal, Stalactitic
Cleavage: Perfect Basal
Rarity: Common
Uses: Collector, Ore of Aluminum
Host rock: Bauxite Deposits, Hydrothermal Veins, Low-temperature Metamorphic Environments
Typical price: $10-50 thumbnail, $50-200 cabinet specimen

Where rockhounds find gibbsite

Classic worldwide localities

Arkansas, USA
Poços de Caldas, Brazil
Les Baux-de-Provence, France
Grythyttan, Sweden
Suriname

Field-hunting tip

Look in bauxite deposits, hydrothermal veins, low-temperature metamorphic environments country — that is the host setting where gibbsite typically forms. If you start seeing boehmite, diaspore, goethite in float, you are in the right ground. Field specimens usually show a tabular crystals, massive, botryoidal, stalactitic habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify gibbsite?+

Mohs hardness is 2.5-3.5. It typically shows a vitreous luster. The streak is white. Common colors include white, grayish-white, yellowish, reddish-white.

Where is gibbsite found?+

Notable localities include Arkansas, USA; Poços de Caldas, Brazil; Les Baux-de-Provence, France; Grythyttan, Sweden; Suriname.

How much is gibbsite worth?+

Typical asking prices fall in the range of $10-50 thumbnail, $50-200 cabinet specimen. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like gibbsite?+

Gibbsite is most often confused with Wavellite, Kaolinite, Diaspore. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with gibbsite?+

Gibbsite commonly co-occurs with Boehmite, Diaspore, Goethite, Hematite, Kaolinite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does gibbsite form in?+

Gibbsite typically forms in bauxite deposits, hydrothermal veins, low-temperature metamorphic environments. Working float back to the host body is the standard way to chase a fresh occurrence.

What is gibbsite used for?+

Gibbsite is used in collector, ore of aluminum.

Find gibbsite on the map

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