opalesce

from WordNet (r) 3.0 (2006)

opalesce
    v 1: reflect light or colors like an opal; "Distant clouds
         opalesce like pale brocade"; "raindrops caught in a sunbeam
         seem to opalesce"
    2: exhibit a play of colors like that of an opal; "This nitrate
       opalesces under certain conditions"

from The Collaborative International Dictionary of English v.0.48

Opalesce \O`pal*esce"\, v. i. [imp. & p. p. {Opalesced}; p. pr.
   & vb. n. {Opalescing}.]
   To give forth a play of colors, like the opal.
   [1913 Webster]

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