How to identify Iron Ore

To correctly identify Iron Ore (Hematite or Magnetite (likely weathered)), 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

   Hematite: Reddish-brown, steel-gray, black. Magnetite: Black. Weathered forms (Limonite/Goethite): Yellowish-brown to dark brown.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Hematite: Earthy to metallic. Magnetite: Metallic to submetallic.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Can be massive, oolitic, botryoidal, specular (hematite), granular, or platy.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Hematite: Rhombohedral, tabular, massive, botryoidal. Magnetite: Isometric, octahedral, granular, massive.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Hematite: None (parting sometimes observed). Magnetite: None.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Banded Iron Formations (BIFs) in ancient sedimentary basins, magmatic intrusions, hydrothermal veins, and lateritic weathering profiles.

Key Facts

Hardness

Hematite: 5-6 on Mohs scale. Magnetite: 5.5-6.5 on Mohs scale.

Specific Gravity

Hematite: 5.26. Magnetite: 5.17-5.20.

Crystal System

Hematite: Trigonal. Magnetite: Isometric.

Color

Hematite: Reddish-brown, steel-gray, black. Magnetite: Black.

Luster

Hematite: Earthy, dull, submetallic, or metallic (specular hematite). Magnetite: Metallic to submetallic.

Transparency

Opaque.

Fracture

Hematite: Uneven to subconchoidal. Magnetite: Uneven to conchoidal.

Cleavage

Hematite: None (parting on {1011} sometimes observed). Magnetite: None.

Composition

Hematite: Iron(III) oxide (Fe2O3). Magnetite: Iron(II,III) oxide (Fe3O4).

Physical characteristics

• Crystal Habit: Hematite: Rhombohedral, tabular, massive, botryoidal, reniform, micaceous (specularite). Magnetite: Octahedral, dodecahedral, granular, massive.
• Cleavage Type: None for both hematite and magnetite. Hematite may exhibit parting.
• Fracture Type: Uneven to subconchoidal (hematite), Uneven to conchoidal (magnetite).
• Tenacity: Brittle.
• Luster Type: Earthy, dull, submetallic, metallic (hematite); Metallic to submetallic (magnetite).

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