We do not currently know of any antonyms for talc.
The noun talc is defined as:
Originally a large range of transparent or glistening foliated minerals. Examples include mica, selenite and the hydrated magnesium silicate that the term talc generally has referred to in modern times (see below). Also an item made of such a mineral and depending for its function on the special nature of the mineral (see next). Mediaeval writers adopted the term from the Arabic.