Source : Webster's Revised Unabridged Dictionary (1913)

Argil \Ar"gil\, n. [F. argile, L. argilla white clay, akin to
   Gr. ? or ? argil, ? white. See {Argent}.] (Min.)
   Clay, or potter's earth; sometimes pure clay, or alumina. See
   {Clay}.

Source : WordNet®

argil
     n : a white clay (especially a white clay used by potters)