|A mass of intergrown pyrite crystals|
|Chemical formula||iron disulfide (FeS2)|
|Color||Pale brass-yellow, tarnishes darker and iridescent|
|Crystal system||Isometric Diploidal, Space group Pa3|
|Mohs Scale hardness||6–6.5|
|Streak||Greenish-black to brownish-black; smells of sulphur|
|Solubility||Insoluble in water|
The mineral pyrite, or iron pyrite, is an iron sulfide with the formula FeS2. This mineral's metallic lustre and pale-to-normal, brass-yellow colour have earned it the nickname fool's gold because of its resemblance to gold.  The term pyrite may also be used for some other sulphides such as copper sulphide.
Pyrite is the most common of the sulphide minerals. In ancient Roman times, this name was applied to several types of stone that would create sparks when struck against steel; Pliny the Elder described one of them as being brassy, almost certainly a reference to what we now call pyrite. By Georgius Agricola's time, the term had become a generic term for all of the sulphide minerals.
Pyrite is usually found associated with other sulphides or oxides in quartz veins, sedimentary rock, and metamorphic rock, as well as in coal beds, and as a replacement mineral in fossils. Despite being nicknamed fool's gold, pyrite is sometimes found in association with small quantities of gold.
- The name pyrite is derived from the Greek πυρίτης (puritēs), "of fire" or "in fire", from πύρ (pur), "fire".
- Julia A. Jackson, James Mehl and Klaus Neuendorf, Glossary of Geology, American Geological Institute (2005) p82.
- Albert H. Fay, A glossary of the mining and mineral industry, United States Bureau of Mines (1920) pp. 103–104.
- Hurlbut, Cornelius S.; Klein, Cornelis 1985. Manual of Mineralogy. 20th ed, John Wiley and Sons, New York. 285–286 ISBN 0-471-80580-7
- Pyrite on webmineral
- Pyrite on Mindat.org
- Handbook of Mineralogy
- James Dwight Dana, Edward Salisbury Dana, Descriptive Minerology, 6th ed., Wiley, New York (1911) p86.
- Herbert Clark Hoover and Lou Henry Hoover, translators of Georgius Agricola, [De Re Metallica], The Mining Magazine, London (1912; Dover reprint, 1950); see footnote, p112.