— chalcedonic /kal'si don"ik/ , chalcedonous , adj.
/kal sed"n ee, kal"seuh doh'nee/ , n. , pl. chalcedonies .
a microcrystalline, translucent variety of quartz, often milky or grayish.
[ 1275-1325; ME calcedonie chalcedonius (Vulgate, Rev. XIX, 19), equiv. to chalcedon- ( chalkedón chalcedony, identified by Saint Jerome with Chalcedon, the city) + -ius -IOUS ]