mineral

Pyrite in Matrix (Fool's Gold)

Iron Disulfide (FeS2)

AI-generated identification · may be incorrect

Hardness: 6-6.5 on Mohs scale; Color: Pale brass-yellow to golden; Luster: Metallic; Crystal Structure: Isometric (cubic/pyritohedral); Cleavage: Indistinct; Specific Gravity: 4.9–5.2.

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

Identified April 11, 2026More mineral →

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Physical properties

Hardness: 6-6.5 on Mohs scale; Color: Pale brass-yellow to golden; Luster: Metallic; Crystal Structure: Isometric (cubic/pyritohedral); Cleavage: Indistinct; Specific Gravity: 4.9–5.2.

Formation & geological history

Formed in hydrothermal veins, as an accessory mineral in igneous rocks, in metamorphic rocks, and in sedimentary rocks (shale, coal, and limestone) through the reduction of sulfates by organic matter.

Uses & applications

Historical source of sulfur and sulfuric acid; used today in the production of sulfur dioxide for paper industry and in some lithium batteries. Often collected as a specimen or used in costume jewelry.

Geological facts

Known as 'Fool's Gold' because its color misled many gold prospectors. It can actually contain small amounts of actual gold as inclusions. It is famous for naturally forming perfect cubes.

Field identification & locations

Identify by its brittle nature (gold is malleable), its blackish-green streak on a porcelain plate, and its high hardness (it can scratch glass). Commonly found worldwide in mining districts like Peru, Spain, and the USA.