Element of reportedly foolish trick (7)
I believe the answer is:
silicon
'element' is the definition.
(silicon is a chemical element)
'reportedly foolish trick' is the wordplay.
I cannot quite see how this works, but
'trick' could be 'con' (a con is a fraud or trick) and 'con' is located in the answer.
This may be the basis of the clue (or it may be nonsense).
'of' acts as a link.
Can you help me to learn more?
(Other definitions for silicon that I've seen before include "Non-metallic element, symbol Si" , "Semiconducting element" , "Element found in chips?" , "Semi-conducting non-metal" , "Element used in making electronic chips" .)