mineral

Pyrite (on Quartz/Host Rock)

Iron Sulfide (FeS₂)

Hardness: 6–6.5 (Mohs scale); Color: Pale brass-yellow to golden yellow; Luster: Metallic; Crystal Structure: Isometric (often cubic or pyritohedral); Cleavage: Indistinct; Specific Gravity: 4.8–5.0

Hardness: 6–6
Color: Pale brass-yellow to golden yellow
Luster: Metallic

Identified March 11, 2026More mineral →

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Physical properties

Formation & geological history

Formed through hydrothermal processes, typically in veins or as replacement minerals in metamorphic or sedimentary environments. It can also form as an accessory mineral in igneous rocks. Age varies based on host rock location, ranging from Precambrian to Cenozoic.

Uses & applications

Predominantly used as an ore of sulfur (for sulfuric acid) and iron. It is also used in jewelry (often sold as 'marcasite'), as a gemstone, and is highly popular among mineral collectors.

Geological facts

Known as 'Fool's Gold' because of its visual similarity to precious metal. Historically, it was used to create sparks for wheel-lock firearms and early fire-starting kits. It is a semiconductor and has been studied for use in photovoltaic solar panels.

Field identification & locations

Identify in the field by its brittle nature (gold is malleable, pyrite will shatter), its blackish-green streak on a porcelain plate, and its cubic crystal habit. It is found globally, with famous deposits in Spain, Peru, Italy, and various locations across the United States including Arizona and Colorado.