Iridescent gem (5)
'iridescent gem' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for pearl that I've seen before include "White - jewel" , "Lustrous structure in a mollusc shell" , "Drop" , "greatly valued" , "coming out of shell?" .)
'iridescent gem' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for opal that I've seen before include "Semi-precious stone of milky or bluish colour" , "Mineral used as a gemstone, of hydrated silica" , "Variegated gemstone" , "Birthstone for October" , "Something milky-white" .)