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 to black (specular hematite), reddish-brown to red (earthy hematite). Goethite: Yellowish-brown, reddish-brown, dark brown to 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: Massive, granular, micaceous (specularite), reniform (kidney ore), botryoidal, oolitic, earthy. Goethite: Massive, fibrous, botryoidal, stalactitic, earthy.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Hematite: Trigonal system, typically tabular, rhombohedral, or massive. Goethite: Orthorhombic system, typically prismatic, acicular, or massive.

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 ancient Precambrian shield areas; lateritic weathering profiles in tropical and subtropical regions; bog iron deposits in wetlands; hydrothermal veins; sedimentary beds and concretions.

Key Facts

Hardness

Hematite: 5-6.5 on Mohs scale. Goethite: 5-5.5 on Mohs scale.

Specific Gravity

Hematite: 5.26. Goethite: 3.3-4.3.

Crystal System

Hematite: Trigonal. Goethite: Orthorhombic.

Color

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

Luster

Hematite: Metallic, submetallic, dull, earthy. Goethite: Adamantine, silky, dull, earthy.

Transparency

Opaque.

Fracture

Hematite: Uneven to subconchoidal. Goethite: Uneven.

Cleavage

Hematite: None (parting common). 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, massive, botryoidal, reniform, oolitic, earthy, micaceous (specularite). Goethite: Prismatic, acicular, fibrous, botryoidal, stalactitic, massive, earthy.
• Cleavage Type: Hematite: None, but parting on {1011} is common. Goethite: Perfect on {010}, but often not visible in massive aggregates.
• 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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