Petrified relic (6)
I believe the answer is:
fossil
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">petrified relic</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for fossil that I've seen before include "Animal remnant preserved in rock" , "Lasting impression" , "Prehistoric remnant" , "This fuel is natural, extracted from the ground" , "The remains of a plant or animal that existed in a past geological age" .)