China clay (6)
I believe the answer is:
kaolin
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">china clay</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for kaolin that I've seen before include "China clay" , "Soft white clay, used for making fine porcelain, say" , "Nil oak in the ceramic clay" .)