Laminated mineral (4)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">laminated mineral</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for mica that I've seen before include "Muscovite with perfect cleavage" , "Flexible mineral found in igneous and metamorphic rocks" , "Shiny silicate mineral" , "Isinglass" , "Transparent mineral" .)