The Collaborative International Dictionary of English v.0.48:

Phillipsite \Phil"lips*ite\, n. [So named after John Phillips,
   an English mineralogist.] (Min.)
   A hydrous silicate of aluminia, lime, and soda, a zeolitic
   mineral commonly occurring in complex twin crystals, often
   cruciform in shape; -- called also christianite.
   [1913 Webster]

WordNet (r) 3.0 (2006):

phillipsite
    n 1: a group of white or reddish crystalline minerals of the
         zeolite family consisting of a hydrous silicate of calcium
         and potassium and aluminum