chalcedony vs calcedony

chalcedony and calcedony both are nouns.

Word	Noun	Adjective	Verb	Adverb
chalcedony	Yes	No	No	No
calcedony	Yes	No	No	No

As nouns, chalcedony and calcedony are synonyms defined as:

chalcedony and calcedony: a milky or greyish translucent to transparent quartz

chalcedony (noun)	calcedony (noun)
a milky or greyish translucent to transparent quartz	a milky or greyish translucent to transparent quartz