Peridotite is a dense, coarse-grained ultramafic igneous rock consisting mostly of olivine and pyroxene. It is the dominant rock type of the Earth's upper mantle and is often found at the surface in ophiolite complexes or as xenoliths brought up by volcanic activity.

Hardness

6-7

Mohs

Luster

Vitreous to dull

Transparency

Opaque

igneouscommon

Peridotite

Hardness: 6-7
Luster: Vitreous to dull
Transparency: Opaque

Is this peridotite?

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 peridotite with a known reference. Peridotite sits at Mohs 6-7, softer than the next harder reference, harder than the previous one.
2
Read the texture
Look at a fresh break with a hand lens. Texture: Phaneritic. Grain size: Coarse-grained.
3
Pick out the minerals
Composition: Mostly olivine and pyroxene; ultramafic, under 45 percent silica. Identify the two or three most abundant grains.
4
Read the luster
Hold the specimen under a strong light. Luster: vitreous to dull.
5
Match the color range
Compare against the expected color range: dark green, olive green, yellow-green.

Often confused with

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

igneous

Basalt

Mohs 6

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

Often found alongside peridotite

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

All properties

Mohs hardness: 6-7
Density: 3.1-3.4 g/cm³
Colors: Dark green Olive green Yellow-green
Luster: Vitreous to dull
Transparency: Opaque
Rarity: Common
Uses: Scientific research, Geological study
Host rock: Earth's mantle
Texture: Phaneritic
Grain size: Coarse-grained
Composition: Mostly olivine and pyroxene; ultramafic, under 45 percent silica

Where rockhounds find peridotite

3 mapped spots

Classic worldwide localities

Oman
South Africa
Norway
USA (Hawaii)
Canada (British Columbia)

Field-hunting tip

Where it forms: Earth's mantle. If you start seeing olivine, pyroxene, chromite in float, you are in the right ground. In the U.S., the densest reported localities are in Kentucky, New York. Start trip planning there.

Browse 3 U.S. spots for peridotite →

Common questions

How do you identify peridotite?+

Mohs hardness is 6-7. Texture: Phaneritic. Composition: Mostly olivine and pyroxene; ultramafic, under 45 percent silica. Luster: vitreous to dull. Common colors include dark green, olive green, yellow-green.

Where is peridotite found?+

Notable localities include Oman; South Africa; Norway; USA (Hawaii); Canada (British Columbia).

Can I find peridotite in the United States?+

RockHoundR maps 3 peridotite rockhounding spots across 2 U.S. states. The top states are Kentucky, New York.

What rocks look like peridotite?+

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

What minerals are found with peridotite?+

Peridotite 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 peridotite form in?+

Where it forms: Earth's mantle. Working float back to the host body is the standard way to chase a fresh occurrence.

What is peridotite used for?+

Peridotite is used in scientific research, geological study.

Find peridotite on the map

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