pyrite

noun

Etymology: Etymology tree Proto-Indo-European *péh₂wr̥ Proto-Hellenic *pāwər Ancient Greek πῦρ (pûr) Proto-Indo-European *-tósder. Ancient Greek -της (-tēs)der. Ancient Greek -ῑ́της (-ī́tēs) Ancient Greek πῠρῑ́της (pŭrī́tēs)bor. Latin pȳritēsder. Old French pyriteder. English pyrite Recorded since 1555, from Old French pyrite (12th century), from Latin pȳritēs, from Ancient Greek πυρίτης λίθος (purítēs líthos, “stone of fire, flint”) (so called because it glitters), notably the first part: adjective πυρίτης (purítēs, “of or in fire”), from πῦρ (pûr, “fire”). Analyzable as pyr- + -ite

1. The common mineral iron disulfide (FeS₂), of a pale brass-yellow color and brilliant metallic luster, crystallizing in the isometric system.

   “The pyrite output in 1961 was 1.2 million tons, derived mainly from the Hsiang Shan mine in Anhwei and the Ying-te mine in Kwangtung.”

   “China's 13 large foreign fertilizer plants ordered a few years ago are all scheduled to be in operation in a year or two.[…]China's biggest pyrite mine (openpit), being built in Yunfu, Kwangtung Province, was near completion.”

2. Any metallic-looking sulphide, such as the above, which is the most common.
3. (usually as a plural: pyrites) Any metal dichalcogenide that is isostructural to the common mineral.

   “Copper diselenide can occur both as a marcasite and a pyrite.”