lignitic

from The Collaborative International Dictionary of English v.0.48

Lignitic \Lig*nit"ic\ (l[i^]g*n[i^]t"[i^]k), a.
   Containing lignite; resembling, or of the nature of, lignite;
   as, lignitic clay.
   [1913 Webster]

   {Lignitic group}. See {Laramie Group}.
      [1913 Webster]