Description: Pyrite, also called iron pyrite or fool’s gold, is a naturally occurring iron disulfide mineral. The name comes from the Greek word pyr, “fire,” because pyrite emits sparks when struck by metal. Pyrite is called fool’s gold; to the novice its color is deceptively similar to that of a gold nugget. Although it is not a significant rock-forming mineral, pyrite is very widespread and is the most common sulfide mineral. It is ubiquitous, found in igneous, metamorphic and sedimentary rocks.

Specimens of pyrite are relatively easy to identify. The mineral always has a brass-yellow color, a metallic luster and feels heavy (having a high specific gravity). Pyrite's streak is black, usually with a tinge of green, and is harder than other yellow metallic minerals.

Pyrite is not processed as a source for iron or sulfur today, but it used to be an important ore for the production of sulfur and sulfuric acid. Pyrite will slowly oxidize in a moist environment, and naturally release sulfuric acid that is formed during the process. This natural process has resulted in environmental problems from old mine leaks and abandoned open pits, where pyrite is an accessory to other sulfides.

Color: Brass yellow, often tarnished to dull brass.

Streak: Greenish black to brownish black

Luster: Metallic

Fracture: Irregular/Uneven, Conchoidal

Cleavage: Poor/Indistinct

Hardness: 6 - 6½ on Moh’s scale

Density/Specific Gravity: 4.8-5 g/cm³

Distinguishing Physical Properties:

• Color: Brass-yellow

• Hardness: harder than other yellow metallic minerals

• Luster: Metallic

• Streak: Greenish black

• Crystals: cubes, octahedrons, etc. and often have striated faces (look closely at specimen photo)

• Specific gravity: feels heavy