Sulphide minerals · Reference guide

Pyrite

Brass-coloured shine and geometric crystals make this iron sulphide a memorable mineral.

General mineral information, separate from our 17 photographed collection specimens.

Composition
FeS₂
Mohs hardness
6–6.5
Read the clues
Appearance can vary

Identification clues

Pyrite is opaque and metallic, usually pale brass-yellow. Cubes are a familiar habit, but it also forms other crystal shapes and granular masses. Fine parallel lines may appear on crystal faces.

Mineral facts and formation

Pyrite occurs in many geological settings, including mineral veins and sedimentary rocks. A cube shape alone does not identify where a specimen came from.

Lookalikes and useful comparisons

Compare its metallic reflection with the moving silky band of Tiger’s Eye. Both can appear golden, but the optical effects are different. Pyrite is brittle; do not bend or hammer a specimen to compare it with gold.

Care for a display specimen

Keep a display specimen dry and avoid soaking. Use a soft dry brush for loose dust. If a piece begins to crumble or develop powder, keep it apart from other specimens and seek collection-care advice.

Look a little closer

Try this observation.

Under ordinary light, compare a flat face with an edge. Note whether the reflection changes across the whole face or forms a narrow moving band.

Does pyrite always form a cube?

No. Cubes are only one of its crystal forms. Rounded aggregates and fine grains may not show obvious cubes at all.

Sources and further reading

Reference information checked 29 September 2026. These sources describe minerals generally; they do not identify a particular stone.

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