chalcedony

Borrowed from Latin chalcēdōnius, probably derived from the name of the town Chalcedon in Asia Minor.

• IPA^(key): /kælˈsɛd.ən.i/, /ˈkæl.səˌdoʊ.ni/

• Audio (US)

  (file)

A cut and polished chalcedony geode.

chalcedony (countable and uncountable, plural chalcedonies)

1. A form of fine-grained quartz that is nearly transparent or has a milky translucence; it fractures conchoidally.
   • 2012 March 1, Lee A. Groat, “Gemstones”, in American Scientist‎, volume 100, number 2, page 128:

     Although there are dozens of different types of gems, among the best known and most important are […] . (Common gem materials not addressed in this article include amber, amethyst, chalcedony, garnet, lazurite, malachite, opals, peridot, rhodonite, spinel, tourmaline, turquoise and zircon.)

• chalcedoneous

• (noun: types of minerals) agate, chert, flint, moganite
• (adjective) conchoidal
• (adverb) conchoidally
• (noun) break, fracture, flake, shatter
• (verb) knapp, break, fracture, flake, shatter

• David Barthelmy (1997–2023), “Chalcedony”, in Webmineral Mineralogy Database.
• “chalcedony”, in Mindat.org‎, Hudson Institute of Mineralogy, 2000–2023.