Form of gypsum (9)
I believe the answer is:
alabaster
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">form of gypsum</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 alabaster that I've seen before include "Type of gypsum" , "statue material" , "Carved form of gypsum" , "White ornamental stone" , "Stab a real odd white mineral" .)