How to identify Iron Ore

To correctly identify Iron Ore (Hematite/Goethite (limonite)), 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: Red, reddish-brown, steel-gray, black. Goethite/Limonite: Yellowish-brown, dark brown, blackish-brown.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Hematite: Metallic (specular hematite), dull to earthy (red ochre). Goethite/Limonite: Silky, dull, earthy.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Hematite: Massive, botryoidal, reniform, micaceous (specularite), earthy. Goethite/Limonite: Massive, botryoidal, stalactitic, earthy, fibrous.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Hematite: Rhombohedral (often tabular or platy), but commonly massive or earthy. Goethite: Orthorhombic (rarely well-formed crystals), typically massive, fibrous, or botryoidal.

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), lateritic weathering profiles, bog iron deposits, hydrothermal veins, sedimentary beds, residual deposits.

Key Facts

Hardness

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

Specific Gravity

Hematite: 5.26; Goethite: 3.3-4.3

Crystal System

Hematite: Trigonal; Goethite: Orthorhombic

Color

Hematite: Red, reddish-brown, steel-gray, black; Goethite: Yellowish-brown, dark brown

Luster

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

Transparency

Opaque

Fracture

Hematite: Uneven to subconchoidal; Goethite: Uneven

Cleavage

Hematite: None (parting present); Goethite: Perfect on {010}, but rarely seen

Composition

Hematite: Iron(III) oxide (Fe2O3); Goethite: Iron(III) oxide-hydroxide (FeO(OH))

Physical characteristics

• Crystal Habit: Hematite: Rhombohedral, tabular, platy, massive, botryoidal, reniform, micaceous (specularite), earthy. Goethite: Prismatic, acicular, fibrous, massive, botryoidal, stalactitic, earthy.
• Cleavage Type: Hematite: No true cleavage, but parting on {1011} is common. Goethite: Perfect on {010}, but often obscured by massive habit.
• 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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