marcasite

From Medieval Latin marchasita et al., from Arabic مَرْقَشِيتَا‎ (marqašītā).

• (UK) IPA^(key): /ˈmɑːkəsʌɪt/
• (US) IPA^(key): /ˈmɑɹ.kə.sɑɪ̯t/, /ˌmɑɹ.kəˈzit/
• Hyphenation: mar‧ca‧site

marcasite (countable and uncountable, plural marcasites)

1. (mineralogy) The orthorhombic form of iron disulfide, FeS₂, occurring as yellow crystals. [from 19th c.]

   Synonym: white iron pyrite

2. (jewellery) Pyrite.
3. (historical) Any of various metal sulfides, usually iron sulfide minerals. [from 15th c.]
   • 1999, Nicholas Goodrick-Clarke, translating Paracelsus, Opus Paramirum, in Essential Readings, North Atlantic Books 1999, p. 95:

     If he wants to speak as a physician, however, he must say, this marcasite is the man's disease, hence it will cure him.

• Marcasite is physically and crystallographically distinct from pyrite, although the two have the same chemical composition.

• golden marcasite

• pyrite

• “Marcasite” in David Barthelmy, Webmineral Mineralogy Database, 1997–.
• “marcasite”, in Mindat.org‎, Hudson Institute of Mineralogy, accessed 29 August 2016.