How to identify Iron Ore

To correctly identify Iron Ore (Hematite/Goethite (Iron Oxide)), 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: Steel gray, silver-gray, reddish-brown, or black. Goethite: Yellowish-brown to dark brown, sometimes black.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Hematite: Metallic to dull earthy. Goethite: Adamantine to dull earthy.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Hematite: Can be massive, botryoidal, reniform, micaceous (specular hematite), or oolitic. Goethite: Typically massive, fibrous, botryoidal, or stalactitic.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Hematite: Rhombohedral, tabular, or platy crystals (specularite). Goethite: Orthorhombic, acicular, prismatic, or tabular crystals, but often massive or fibrous.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Hematite: No true cleavage, but parting along rhombohedral planes can occur. Goethite: Perfect cleavage on {010}, but rarely observed in massive forms.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Banded Iron Formations (BIFs) in Precambrian shield areas, lateritic weathering profiles, bog iron deposits, hydrothermal veins, and sedimentary beds.

Key Facts

Hardness

Hematite: 5-6.5 (Mohs). Goethite: 5-5.5 (Mohs).

Specific Gravity

Hematite: 4.9-5.3. Goethite: 3.3-4.3.

Crystal System

Hematite: Trigonal. Goethite: Orthorhombic.

Color

Hematite: Steel gray, reddish-brown, black. Goethite: Yellowish-brown to dark brown.

Luster

Hematite: Metallic to dull earthy. Goethite: Adamantine to dull earthy.

Transparency

Opaque.

Fracture

Hematite: Uneven to subconchoidal. Goethite: Uneven.

Cleavage

Hematite: None, but parting on {1011}. Goethite: Perfect on {010}, but rarely seen.

Composition

Hematite: Iron(III) oxide (Fe2O3). Goethite: Iron(III) oxyhydroxide (FeO(OH)).

Physical characteristics

• Crystal Habit: Hematite: Rhombohedral, tabular, platy, massive, botryoidal, reniform, oolitic. Goethite: Prismatic, acicular, tabular, massive, fibrous, botryoidal, stalactitic.
• Cleavage Type: Hematite: No true cleavage, but parting. Goethite: Perfect on {010}.
• Fracture Type: Hematite: Uneven to subconchoidal. Goethite: Uneven.
• Tenacity: Brittle.
• Luster Type: Hematite: Metallic, submetallic, dull, earthy. Goethite: Adamantine, silky, dull, earthy.

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