Carbonatite is a rare igneous rock composed of more than 50% carbonate minerals rather than the typical silicate minerals found in most igneous rocks. They are of significant interest to collectors and geologists because they are the world's primary source of rare earth elements, niobium, and apatite.

Hardness

3-4

Mohs

Luster

Vitreous to dull

Transparency

Opaque

igneousrare

Carbonatite

Hardness: 3-4
Luster: Vitreous to dull
Transparency: Opaque

Is this carbonatite?

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 carbonatite with a known reference. Carbonatite sits at Mohs 3-4, 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: Coarse (sovite) or finer (alvikite).
3
Pick out the minerals
Composition: Over 50 percent carbonate minerals; may include apatite, magnetite, baryte, fluorite, natrolite or sodalite. 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: white, gray, tan, pink, brown.

Often confused with

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

metamorphic

Marble

Mohs 3-4

How to tell apart: Luster reads vitreous to dull on Carbonatite and subvitreous on Marble.

How to tell apart: Luster reads vitreous to dull on Carbonatite and dull to earthy on Limestone.

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Often found alongside carbonatite

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

All properties

Mohs hardness: 3-4
Density: 2.7-3.0 g/cm³
Colors: White Gray Tan Pink Brown
Luster: Vitreous to dull
Transparency: Opaque
Rarity: Rare
Uses: Industrial, Scientific research
Host rock: intrusive igneous complexes
Texture: Coarse (sovite) or finer (alvikite)
Composition: Over 50 percent carbonate minerals; may include apatite, magnetite, baryte, fluorite, natrolite or sodalite

Where rockhounds find carbonatite

Classic worldwide localities

Fen Complex, Norway
Kola Peninsula, Russia
Mount Weld, Australia
Palabora, South Africa
Mountain Pass, USA

Field-hunting tip

Where it forms: intrusive igneous complexes. If you start seeing calcite, dolomite, apatite in float, you are in the right ground.

Common questions

How do you identify carbonatite?+

Mohs hardness is 3-4. Texture: Coarse (sovite) or finer (alvikite). Composition: Over 50 percent carbonate minerals; may include apatite, magnetite, baryte, fluorite, natrolite or sodalite. Luster: vitreous to dull. Common colors include white, gray, tan, pink.

Where is carbonatite found?+

Notable localities include Fen Complex, Norway; Kola Peninsula, Russia; Mount Weld, Australia; Palabora, South Africa; Mountain Pass, USA.

What rocks look like carbonatite?+

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

What minerals are found with carbonatite?+

Carbonatite commonly co-occurs with calcite, dolomite, apatite, magnetite, phlogopite, pyrochlore. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does carbonatite form in?+

Where it forms: intrusive igneous complexes. Working float back to the host body is the standard way to chase a fresh occurrence.

What is carbonatite used for?+

Carbonatite is used in industrial, scientific research.

Find carbonatite on the map

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