How to identify Iron Ore

To correctly identify Iron Ore (Hematite or Magnetite (likely a mixture)), 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, dark gray.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Hematite: Metallic to dull, earthy. Magnetite: Metallic to submetallic.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

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

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Hematite: Rhombohedral, tabular, botryoidal, reniform, massive. Magnetite: Octahedral, dodecahedral, granular, massive.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Hematite: None (parting may be observed). Magnetite: None (parting on {111} may be observed).

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Banded Iron Formations (BIFs) in ancient Precambrian shield areas; magmatic segregations in mafic and ultramafic igneous rocks; contact metamorphic deposits; hydrothermal veins; lateritic weathering profiles; sedimentary placers.

Key Facts

Hardness

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

Specific Gravity

Hematite: 4.9-5.3; Magnetite: 5.17-5.18

Crystal System

Hematite: Trigonal; Magnetite: Isometric

Color

Hematite: Reddish-brown, steel-gray, black; Magnetite: Black, dark gray

Luster

Hematite: Metallic to dull/earthy; Magnetite: Metallic to submetallic

Transparency

Opaque

Fracture

Hematite: Uneven to subconchoidal; Magnetite: Uneven to conchoidal

Cleavage

None (parting may be observed in both)

Composition

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

Physical characteristics

• Crystal Habit: Hematite: Rhombohedral, tabular, botryoidal, reniform, massive, micaceous (specular). Magnetite: Octahedral, dodecahedral, granular, massive.
• Cleavage Type: None, but parting may occur in both minerals.
• Fracture Type: Uneven to subconchoidal (hematite), Uneven to conchoidal (magnetite).
• Tenacity: Brittle
• Luster Type: Metallic, submetallic, dull, earthy.

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