mineral

Pyrite

Iron Disulfide (FeS2)

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

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

Identified July 4, 2026More mineral →

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Physical properties

Hardness: 6-6.5; Color: Pale 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 magmatic segregation, hydrothermal veins, and sedimentary rocks under reducing conditions. It is the most common sulfide mineral.

Uses & applications

Historically used as a source of sulfur and sulfuric acid. Today used in jewelry (as marcasite), in radio receivers, and primarily as a collector's specimen.

Geological facts

Often called Fool's Gold because of its yellowish metallic luster, Pyrite can actually create sparks when struck against steel, which made it a common ignition source for early firearms.

Field identification & locations

Identify by its brassy color, cubic or octahedral crystal habits, and its greenish-black streak (real gold has a yellow streak). Found globally in places like Spain, Peru, and the USA.