mineral

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Hardness: 6-6.5 on Mohs scale; Color: brass-yellow, metallic gold; Luster: metallic; Crystal Structure: isometric (cubic); Cleavage: poor/indistinct; Specific Gravity: 4.9-5.2

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

Identified February 20, 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/indistinct; Specific Gravity: 4.9-5.2

Formation & geological history

Formed in high and low temperature hydrothermal veins, by magmatic segregation, or as an accessory mineral in igneous and sedimentary rocks. Common in coal beds and as a replacement mineral in fossils.

Uses & applications

Primarily used for the production of sulfur dioxide, which is used in the paper industry and to manufacture sulfuric acid. Occasionally used as a gemstone (marcasite jewelry) and as an ornamental stone.

Geological facts

It is nicknamed 'Fool's Gold' because its color and high density often lead novice prospectors to mistake it for real gold. Unlike gold, it is brittle and will shatter if struck rather than flatten.

Field identification & locations

Identify by its cubic crystal habit, brassy color, and greenish-black streak when rubbed on a porcelain plate. Found globally in diverse geological settings like Peru, Spain, and the USA (e.g., Leadville, Colorado).