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Roaldite is an extremely rare iron-nickel nitride mineral that occurs primarily as microscopic inclusions within iron meteorites. It is almost never found in hand-specimens and is typically identified through metallurgical analysis or electron microscopy of meteorite sections.

Hardness
5.5-6.5
Mohs
Luster
Metallic
Streak
White
Transparency
Opaque

Is this roaldite?

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 roaldite with a known reference. Roaldite sits at Mohs 5.5-6.5, softer than the next harder reference, harder than the previous one.
  • 2
    Check the streak
    Drag the specimen across an unglazed porcelain plate. Streak: white.
  • 3
    Read the luster
    Hold the specimen under a strong light. Luster: metallic.
  • 4
    Match the color range
    Compare against the expected color range: tin white.
  • 5
    Look at form & habit
    Crystal system: cubic. Typical habit: microscopic grains and inclusions.

Often confused with

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

Etched iron meteorite slice showing kamacite Widmanstätten lamellae
mineral
Kamacite
Mohs 4

How to tell apart: Roaldite is noticeably harder (Mohs 5.5-6.5 vs. 4); streak differs, so Roaldite leaves white, Kamacite leaves gray.

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Taenite mineral
mineral
Taenite
Mohs 5-5.5

How to tell apart: Streak differs, so Roaldite leaves white, Taenite leaves light gray.

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Often found alongside roaldite

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

All properties

Chemical formula
(Fe,Ni)₄N
Mohs hardness
5.5-6.5
Density
7.21 g/cm³
Colors
Tin white
Streak
White
Luster
Metallic
Transparency
Opaque
Crystal system
Cubic
Crystal habit
Microscopic grains and inclusions
Cleavage
None
Rarity
Rare
Uses
Collector
Host rock
A rare accessory mineral in iron-nickel meteorites, probably formed by diffusion of nitrogen

Where rockhounds find roaldite

Classic worldwide localities

  • Jerslev, Youndegin, and Canyon Diablo iron meteorites

Field-hunting tip

Where it forms: A rare accessory mineral in iron-nickel meteorites, probably formed by diffusion of nitrogen. If you start seeing kamacite, cohenite, schreibersite in float, you are in the right ground. Typical habit: microscopic grains and inclusions. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify roaldite?+
Mohs hardness is 5.5-6.5. Luster: metallic. The streak is white. Common colors include tin white.
Where is roaldite found?+
Notable localities include Jerslev, Youndegin, and Canyon Diablo iron meteorites.
Is roaldite safe to handle?+
Roaldite 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 roaldite?+
Roaldite is most often confused with Kamacite, Taenite. A quick hardness test and a streak check separate the look-alikes faster than color alone.
What minerals are found with roaldite?+
Roaldite commonly co-occurs with Kamacite, Cohenite, Schreibersite, Carlsbergite, Daubreelite. Spotting any of these in float or country rock is a useful trip signal.
What kind of rock does roaldite form in?+
Where it forms: A rare accessory mineral in iron-nickel meteorites, probably formed by diffusion of nitrogen. Working float back to the host body is the standard way to chase a fresh occurrence.
What is roaldite used for?+
Roaldite is used in collector.

Find roaldite on the map

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