argent (n.) Look up argent at
early 15c., "silver, silver coin," from Old French argent "silver, silver money; quicksilver" (11c.), from Latin argentum "silver, silver work, silver money," from PIE *arg-ent- (source also of Avestan erezata-, Old Persian ardata-, Armenian arcat, Old Irish argat, Breton arc'hant "silver"), from root *arg- "to shine; white," thus "silver" as "the shining or white metal" (source also of Greek argos "white," arguron "silver;" Sanskrit arjuna- "white, shining," rajata- "silver," Hittite harki- "white").

Earlier in English in the sense "quicksilver, the metal mercury" (c. 1300); the adjective sense "silver-colored" is from late 15c.