mineral

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Hardness: 6-6.5 on Mohs scale; Color: brass-yellow, metallic gold; Luster: metallic; Crystal structure: isometric/cubic; Cleavage: poor; Specific gravity: 4.9-5.2.

Hardness: 6-6
Color: brass-yellow, metallic gold
Luster: metallic

Identified May 21, 2026More mineral →

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Physical properties

Hardness: 6-6.5 on Mohs scale; Color: brass-yellow, metallic gold; Luster: metallic; Crystal structure: isometric/cubic; Cleavage: poor; Specific gravity: 4.9-5.2.

Formation & geological history

Forms in high and low temperature hydrothermal veins, by segregation from magmas, and as an accessory mineral in igneous, metamorphic, and sedimentary rocks. It is found across all geological ages.

Uses & applications

Primarily used in the production of sulfur dioxide for the paper industry and sulfuric acid for chemical manufacturing. Occasionally used in inexpensive jewelry (marcasite) and as a collector's specimen.

Geological facts

The name Pyrite comes from the Greek 'pyr' meaning fire, because it emits sparks when struck by metal. It is the most common sulfide mineral and is often mistaken for gold, though gold is much softer, denser, and leaves a yellow streak (whereas pyrite leaves a greenish-black streak).

Field identification & locations

Identify by its brittle nature, cubic crystal shapes, and greenish-black streak. Common in mining districts worldwide; notable locations include Spain (Rio Tinto), Peru, and the USA. For collectors, look for well-defined cubic or dodecahedron shapes.