Heraldic black (5)
I believe the answer is:
sable
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">heraldic black</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for sable that I've seen before include "Type of fur" , "North Asian marten" , "Bales of valuable Russian fur" , "Dark brown - black" , "(Fur from) small carnivore" .)