How to identify Iron Ore

To correctly identify Iron Ore (Hematite or Goethite (likely a mix of iron oxides/hydroxides)), 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: Can be massive, botryoidal, reniform, micaceous (specularite), or earthy. Goethite: Can be massive, stalactitic, botryoidal, 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, botryoidal, or earthy. Goethite: Orthorhombic crystals (rarely well-formed), typically acicular, fibrous, stalactitic, 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 in tropical regions; hydrothermal veins; sedimentary deposits (bog iron ores).

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: Steel-gray, black, reddish-brown, red. Goethite: Yellowish-brown, reddish-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 {010} (rarely observed).

Composition

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

Physical characteristics

• Crystal Habit: Hematite: Rhombohedral, tabular, platy, micaceous (specularite), botryoidal, reniform, massive, earthy. Goethite: Acicular, fibrous, stalactitic, botryoidal, massive, earthy.
• Cleavage Type: Hematite: None (rhombohedral parting). Goethite: Perfect {010} (rarely seen).
• Fracture Type: Uneven to subconchoidal.
• Tenacity: Brittle.
• Luster Type: Metallic, submetallic, adamantine, silky, dull earthy.

Explore Iron Ore