How to identify Iron Ore

To correctly identify Iron Ore (Hematite/Goethite (likely a mixture of iron oxides)), 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 earthy red (ocherous 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: Can be massive, botryoidal, reniform, micaceous (specularite), or earthy. Goethite: Typically massive, fibrous, botryoidal, or stalactitic.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Hematite: Rhombohedral (trigonal system), often tabular, platy, or granular. Goethite: Orthorhombic, typically acicular, fibrous, 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 {010} cleavage, but rarely observed in massive forms.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Banded Iron Formations (BIFs) in ancient cratons, lateritic weathering profiles, sedimentary ironstones, hydrothermal veins, and contact metamorphic zones.

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

Variable: steel-gray, black, reddish-brown, yellow-brown.

Luster

Metallic, submetallic, dull, earthy.

Transparency

Opaque.

Fracture

Hematite: Uneven to subconchoidal. Goethite: Uneven.

Cleavage

Hematite: None (parting present). Goethite: Perfect {010} (rarely observed).

Composition

Iron oxides and hydroxides (Fe2O3, FeO(OH)).

Physical characteristics

• Crystal Habit: Hematite: Massive, botryoidal, reniform, micaceous (specularite), tabular, granular, earthy. Goethite: Massive, fibrous, botryoidal, stalactitic, acicular.
• Cleavage Type: Hematite: None (parting along {1011} planes). Goethite: Perfect {010} (rarely seen in massive forms).
• Fracture Type: Hematite: Uneven to subconchoidal. Goethite: Uneven.
• Tenacity: Brittle.
• Luster Type: Metallic, submetallic, dull, earthy.

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