Tufa

2 definitions found

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  Tufa \Tu"fa\, [It. fufo soft, sandy stone, L. tofus, tophus. Cf.
     {Tofus}, {Toph}, and {Tophin}.] (Min.)
     (a) A soft or porous stone formed by depositions from water,
         usually calcareous; -- called also {calcareous tufa}.
     (b) A friable volcanic rock or conglomerate, formed of
         consolidated cinders, or scoria.


         [1913 Webster]

From WordNet (r) 2.0 [wn]:

  tufa
       n 1: a soft porous rock consisting of calcium carbonate deposited
            from springs rich in lime [syn: {calc-tufa}]
       2: hard volcanic rock composed of compacted volcanic ash [syn:
          {tuff}]