1550s, from Medieval Latin talcum, used for any of various shiny minerals. See talc. Talcum powder attested from 1871.
Entries linking to talcum
talc n.
1580s, talke, from French talc (16c.), probably from Spanish talco and Medieval Latin talcus, also talcum "talc" (ealy 14c.), both from Arabic talq, from Persian talk "talc." "It was applied by the Arab and medieval writers to various transparent, translucent and shining minerals such as talc proper, mica, selenite, etc." [Flood]. Related: Talcoid; talcose; talcous.