The Collaborative International Dictionary of English v.0.48:

Stereochromy \Ste`re*och"ro*my\, n. [Stereo- + Gr. chrw^ma
   color.]
   A style of painting on plastered walls or stone, in which the
   colors are rendered permanent by sprinklings of water, in
   which is mixed a proportion of soluble glass (a silicate of
   soda).
   [1913 Webster]