Why is the ninth month called September?
1580s, from Middle French talc, probably from Spanish talco and Medieval Latin 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].
A fine-grained white, greenish, or gray mineral, having a soft soapy feel and used in talcum and face powder. Also called talcum.
talcum tal·cum (tāl'kəm)
A very soft white, greenish, or gray monoclinic mineral usually occurring as massive micalike flakes in igneous or metamorphic rocks. It has a soapy texture and is used in face powder and talcum powder, for coating paper, and as a filler in paints and plastics. Chemical formula: Mg3Si4O10(OH)2.