Kamacite is the iron-nickel alloy that is a major constituent of iron meteorites, typically about 90 to 95 percent iron. The IMA treats it as a nickel-rich variety of native iron rather than a separate species. In octahedrite meteorites it forms bands interleaved with taenite, producing the Widmanstätten pattern seen on etched slices. It is steel-gray to iron-black, metallic and magnetic, with a hardness of about 4 and a density near 7.9 g/cm³. The Handbook of Mineralogy also lists rare occurrences in rocks on Earth, including Disko Island, Greenland.

Hardness

Mohs

Luster

Metallic

Streak

Gray

Transparency

Opaque

mineralNative Iron family

Kamacite

Hardness: 4
Luster: Metallic
Streak: Gray
Transparency: Opaque

Is this kamacite?

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 kamacite with a known reference. Kamacite sits at Mohs 4, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: gray.
3
Read the luster
Hold the specimen under a strong light. Luster: metallic.
4
Match the color range
Compare against the expected color range: steel gray, iron black.
5
Look at form & habit
Crystal system: cubic. Typical habit: plates and lamellar masses; bands in Widmanstätten patterns.

Often confused with

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

mineral

Taenite

Mohs 5-5.5

How to tell apart: Taenite is the harder of the two (Mohs 5-5.5 vs. 4); streak differs, so Kamacite leaves gray, Taenite leaves light gray.

Compare →

Often found alongside kamacite

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

All properties

Chemical formula: α-(Fe,Ni)
Mohs hardness: 4
Density: 7.9 g/cm³
Colors: Steel gray Iron black
Streak: Gray
Luster: Metallic
Transparency: Opaque
Crystal system: Cubic
Crystal habit: Plates and lamellar masses; bands in Widmanstätten patterns
Cleavage: Indistinct
Host rock: A major constituent of iron meteorites and present in most other meteorites

Where rockhounds find kamacite

Classic worldwide localities

Iron meteorites
Blaafjeld, Disko Island, Greenland (terrestrial)
Bühl, near Weimar, Germany (terrestrial)
Putorana Plateau, Taimyr Peninsula, Russia (terrestrial)

Field-hunting tip

Where it forms: A major constituent of iron meteorites and present in most other meteorites. If you start seeing taenite, graphite, cohenite in float, you are in the right ground. Typical habit: plates and lamellar masses; bands in Widmanstätten patterns. Train your eye for that shape before scanning the outcrop.

More kamacite photos

Common questions

How do you identify kamacite?+

Mohs hardness is 4. Luster: metallic. The streak is gray. Common colors include steel gray, iron black.

Where is kamacite found?+

Notable localities include Iron meteorites; Blaafjeld, Disko Island, Greenland (terrestrial); Bühl, near Weimar, Germany (terrestrial); Putorana Plateau, Taimyr Peninsula, Russia (terrestrial).

Is kamacite safe to handle?+

Kamacite contains nickel. Wash your hands afterwards, never grind or breathe the dust, and store it apart from specimens you handle often.

What rocks look like kamacite?+

Kamacite is most often confused with Taenite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with kamacite?+

Kamacite commonly co-occurs with Taenite, Graphite, Cohenite, Moissanite, Schreibersite, Troilite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does kamacite form in?+

Where it forms: A major constituent of iron meteorites and present in most other meteorites. Working float back to the host body is the standard way to chase a fresh occurrence.

Find kamacite on the map

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