1. 
[syn: iridescent, nacreous, opalescent, opaline, pearlescent]
The Collaborative International Dictionary of English v.0.48:
Opaline \O"pal*ine\, a. [Cf. F. opalin.]
   Of, pertaining to, or like, opal in appearance; having
   changeable colors like those of the opal.
   [1913 Webster]
The Collaborative International Dictionary of English v.0.48:
Opaline \O"pal*ine\, n.
   1. An opaline variety of yellow chalcedony.
      [Webster 1913 Suppl.]
   2. Opal glass.
      [Webster 1913 Suppl.]
   3. An opaline color or expanse.
      [Webster 1913 Suppl.]
WordNet (r) 3.0 (2006):
opaline
    adj 1: having a play of lustrous rainbow colors; "an iridescent
           oil slick"; "nacreous (or pearlescent) clouds looking
           like mother-of-pearl"; "a milky opalescent (or opaline)
           luster" [syn: iridescent, nacreous, opalescent,
           opaline, pearlescent]