The Collaborative International Dictionary of English v.0.48:

Pseudomorphous \Pseu`do*mor"phous\, a. [Gr. ?; pseydh`s false +
   morfh` form: cf. F. pseudomorphe.]
   Not having the true form.
   [1913 Webster]

   Pseudomorphous crystal, a crystal which has a form that
      does not result from its own powers of crystallization.
      [1913 Webster]