chalcedony

UK: /kælˈsɛdənɪ/ US: (kal sed′n ē, kal′sə dō′nē)

Inflections of 'chalcedony' (n): npl: chalcedonies

WordReference Random House Unabridged Dictionary of American English © 2026

chal•ced•o•ny  (kal sed′n ē, kal′sə dō′nē), n., pl. -nies. 

1. a microcrystalline, translucent variety of quartz, often milky or grayish.

• Greek chalkēdó̄n chalcedony, identified by Saint Jerome with Chalcedon, the city) + -ius -ious
• Late Latin chalcēdōnius (Vulgate, Rev. XIX, 19), equivalent. to chalcēdōn- (
• 1275–1325; Middle English calcedonie

chal•ce•don•ic  (kal′si don′ik), chal•ced′o•nous, adj. 

Collins Concise English Dictionary © HarperCollins Publishers::

chalcedony / kælˈsɛdənɪ/, calcedony noun ( -nies)

1. a microcrystalline often greyish form of quartz with crystals arranged in parallel fibres: a gemstone. Formula: SiO₂

Etymology: 15th Century: from Late Latin chalcēdōnius, from Greek khalkēdōn a precious stone (Revelation 21:19), perhaps named after Khalkēdōn Chalcedon, town in Asia Minor

chalcedonic / ˌkælsɪˈdɒnɪk/ adjective