mineral

Pyrite

Iron Sulfide (FeS2)

Hardness: 6-6.5 on Mohs scale; Color: Brass-yellow, metallic gold; Luster: Metallic; Crystal Structure: Isometric (often cubic or dodecahedral); Cleavage: Indistinct; Specific Gravity: 4.9-5.2.

Hardness: 6-6
Color: Brass-yellow, metallic gold
Luster: Metallic

Identified July 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 (often cubic or dodecahedral); Cleavage: Indistinct; Specific Gravity: 4.9-5.2.

Formation & geological history

Formed in a variety of environments including hydrothermal veins, sedimentary rocks (via biological activity), and as an accessory mineral in igneous rocks. It can form in oxygen-poor environments where sulfur and iron are present.

Uses & applications

Historically used as a source of sulfur and sulfuric acid. Today, it is primarily used for jewelry (known as 'marcasite' in the trade), as a specimen for collectors, and in the production of lithium batteries.

Geological facts

Often called 'Fool\'s Gold' because its color resembles gold, though it is much harder and more brittle. When struck against steel, it produces sparks, leading to its name derived from the Greek word 'pyr' meaning fire.

Field identification & locations

Identify by its hardness (cannot be scratched by a copper penny, unlike gold) and its greenish-black streak when rubbed against a porcelain plate. Common locations include Peru, Spain, and the USA.