The Collaborative International Dictionary of English v.0.48:

Flucan \Flu"can\, n. (Mining)
   Soft clayey matter in the vein, or surrounding it. [Written
   also flookan, flukan, and fluccan.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Flookan \Flook"an\, Flukan \Flu"kan\, n. (Mining)
   See Flucan.
   [1913 Webster]