How to identify Iron Meteorite

To correctly identify Iron Meteorite (Iron-Nickel Meteorite), check each of these features in order. Many rocks and minerals look alike, so cross-reference multiple properties before deciding.

Step-by-step identification

1. 1

   Color

   Overall color and any zoning or banding

   Freshly cut surfaces are silvery-gray to steel-gray. Weathered surfaces are typically reddish-brown to dark brown due to oxidation (rusting).

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Metallic luster on fresh surfaces. Dull to earthy on weathered surfaces.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Dense, compact. When cut, polished, and etched, displays the characteristic Widmanstätten pattern (interlocking bands of kamacite and taenite).

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Macroscopic crystals are not typically visible without etching. The internal structure reveals intergrown lamellae of kamacite (body-centered cubic Fe-Ni alloy) and taenite (face-centered cubic Fe-Ni alloy).

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   No distinct cleavage. Exhibits hackly fracture.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Not formed in terrestrial geological environments. Found as meteorites on Earth's surface, having fallen from space. Often found in arid regions (deserts) or polar ice fields where preservation is better and terrestrial rocks are less abundant.

Key Facts

Hardness

4-5 on Mohs scale (for kamacite and taenite)

Specific Gravity

7.8-8.0 g/cm³ (significantly higher than most terrestrial rocks)

Crystal System

Cubic (for kamacite and taenite)

Color

Silvery-gray to steel-gray (fresh), reddish-brown to dark brown (weathered)

Luster

Metallic

Transparency

Opaque

Fracture

Hackly, irregular

Cleavage

None

Composition

Primarily iron (Fe) and nickel (Ni) alloys, typically 5-25% nickel. Minor amounts of cobalt, phosphorus (as schreibersite), sulfur (as troilite), and carbon (as cohenite or graphite).

Physical characteristics

• Crystal Habit: Massive, often irregular shapes. Internally, intergrown lamellae of kamacite and taenite forming the Widmanstätten pattern when etched.
• Cleavage Type: Absent
• Fracture Type: Hackly, irregular, tough
• Tenacity: Malleable to tough
• Luster Type: Metallic

Explore Iron Meteorite