bentonite

from WordNet (r) 3.0 (2006)
bentonite
    n 1: an absorbent aluminum silicate clay formed from volcanic
         ash
    
from The Collaborative International Dictionary of English v.0.48
bentonite \bentonite\ n.
   an absorbent aluminum silicate clay formed from volcanic ash.
   [WordNet 1.5]
    

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