Oyster bead (5)
I believe the answer is:
pearl
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">oyster bead</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 pearl that I've seen before include "Drop" , "Gem; size of type" , "Paragon" , "something highly valued" , "Lustrous structure in a mollusc shell" .)