Komatiite is a rare ultramafic volcanic rock characterized by its unique spinifex texture formed by rapid cooling of magnesium-rich lava. It is primarily found in Archean greenstone belts and represents some of the hottest volcanic eruptions in Earth's early history.

Hardness

5-6

Mohs

Luster

Dull

Streak

White

Transparency

Opaque

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Komatiite

Hardness: 5-6
Luster: Dull
Streak: White
Transparency: Opaque

Is this komatiite?

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 komatiite with a known reference. Komatiite sits at Mohs 5-6, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Komatiite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Komatiite typically shows a dull luster.
4
Match the color range
Compare against the expected color range: dark gray, greenish-gray, black.
5
Look at form & habit
Typical habit: massive.

Often confused with

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

How to tell apart: Luster reads dull on Komatiite and vitreous to dull on Peridotite.

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Often found alongside komatiite

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

All properties

Mohs hardness: 5-6
Density: 2.8-3.3 g/cm³
Colors: Dark Gray Greenish-gray Black
Streak: White
Luster: Dull
Transparency: Opaque
Crystal habit: Massive
Cleavage: None
Rarity: Rare
Uses: Geological Research, Collector
Host rock: Archean Volcanic Sequences
Typical price: $10-50 per specimen

Where rockhounds find komatiite

Classic worldwide localities

Barberton Greenstone Belt, South Africa
Abitibi Greenstone Belt, Canada
Yilgarn Craton, Australia
Finland

Field-hunting tip

Look in archean volcanic sequences country, the host setting where komatiite typically forms. If you start seeing olivine, pyroxene, chromite in float, you are in the right ground. Field specimens usually show a massive habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify komatiite?+

Mohs hardness is 5-6. It typically shows a dull luster. The streak is white. Common colors include dark gray, greenish-gray, black.

Where is komatiite found?+

Notable localities include Barberton Greenstone Belt, South Africa; Abitibi Greenstone Belt, Canada; Yilgarn Craton, Australia; Finland.

How much is komatiite worth?+

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

What rocks look like komatiite?+

Komatiite is most often confused with Basalt, Peridotite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with komatiite?+

Komatiite commonly co-occurs with olivine, pyroxene, chromite, serpentine. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does komatiite form in?+

Komatiite typically forms in archean volcanic sequences. Working float back to the host body is the standard way to chase a fresh occurrence.

What is komatiite used for?+

Komatiite is used in geological research, collector.

Find komatiite on the map

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