The Collaborative International Dictionary of English v.0.48:

Petrification \Pet`ri*fi*ca"tion\, n. [Cf. F. p['e]trification.
   See Petrify.]
   1. See Petrifaction.
      [1913 Webster]

   2. Fig.: Obduracy; callousness. --Hallywell.
      [1913 Webster]

WordNet (r) 3.0 (2006):

petrification
    n 1: the process of turning some plant material into stone by
         infiltration with water carrying mineral particles without
         changing the original shape [syn: petrifaction,
         petrification]