Executed search after extremely rough diamond (5)
I believe the answer is:
rhomb
'diamond' is the definition.
(I know that diamond can be written as rhomb)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for rhomb that I've seen before include "Four-sided figure" , "Quadrilateral with four equal sides" , "Figure on plane" , "Equilateral parallelogram" , "Crystal shape" .)