Small loose stones (6)
I believe the answer is:
gravel
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">small loose stones</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 gravel that I've seen before include "Loose fragments of rock" , "Stone mixture for paths" , "Small fragments of rock" , "Rock fragments and pebbles" , "Small stones on paths" .)