mineral

Pyrite

Iron Disulfide (FeS2)

Hardness: 6-6.5 Mohs scale; Color: Brass-yellow; Luster: Metallic; Crystal Structure: Isometric; Cleavage: Poor/Indistinct; Specific Gravity: 4.9-5.2

Hardness: 6-6
Color: Brass-yellow
Luster: Metallic

Identified July 3, 2026More mineral →

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Physical properties

Hardness: 6-6.5 Mohs scale; Color: Brass-yellow; Luster: Metallic; Crystal Structure: Isometric; Cleavage: Poor/Indistinct; Specific Gravity: 4.9-5.2

Formation & geological history

Forms in a wide variety of environments including igneous, metamorphic, and sedimentary rocks. It often grows in hydrothermal veins or as replacement minerals in fossils. It can be found in rocks from the Precambrian era to the present.

Uses & applications

Historically a source of sulfur and sulfuric acid. Today, it is used in the manufacture of sulfur dioxide and in lithium batteries. It is also used as a gemstone and popular collector specimen.

Geological facts

Widely known as 'Fool's Gold' because its color and metallic luster frequently led novice prospectors to mistake it for real gold. Unlike gold, pyrite is brittle and leaves a greenish-black streak when rubbed on a streak plate.

Field identification & locations

Identify by its hardness (it can scratch glass, gold cannot) and its brittle nature (it crushes into powder, gold flattens). Commonly found in coal beds, quartz veins, and sedimentary shales. Collectors should store it in low humidity to prevent 'pyrite disease' (oxidation).