Iridescent gem (4)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">iridescent gem</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(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?" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">iridescent gem</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(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" .)