How to identify Iron Ore

To correctly identify Iron Ore (Iron Ore (Hematite/Goethite)), 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, or black. Goethite: Yellowish-brown, dark brown, reddish-brown.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

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

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

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

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Hematite: Rhombohedral crystals (often tabular or platy), but more commonly massive or earthy. Goethite: Orthorhombic crystals, but typically found in massive, fibrous, or botryoidal aggregates.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Hematite: No true cleavage, but may exhibit parting. 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; hydrothermal veins; sedimentary deposits (e.g., oolitic ironstone).

Key Facts

Hardness

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

Specific Gravity

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

Crystal System

Hematite: Trigonal. Goethite: Orthorhombic.

Color

Hematite: Red, reddish-brown, steel-gray, black. Goethite: Yellowish-brown, dark brown, reddish-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 common). Goethite: Perfect on {010}, but rarely seen.

Composition

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

Physical characteristics

• Crystal Habit: Hematite: Rhombohedral, tabular, platy, massive, botryoidal, reniform, earthy, micaceous (specular). Goethite: Prismatic, acicular, fibrous, botryoidal, stalactitic, massive, earthy.
• Cleavage Type: Hematite: None (parting on {1011} and {0001} due to twinning or exsolution). Goethite: Perfect on {010}, but often not visible in massive forms.
• Fracture Type: Uneven to subconchoidal (hematite); Uneven (goethite).
• Tenacity: Brittle.
• Luster Type: Metallic, submetallic, dull, earthy (hematite); Adamantine, silky, dull, earthy (goethite).

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