Circling end of pier, fancy eating rock (7)
I believe the answer is:
granite
'rock' is the definition.
(I've seen this before)
'circling end of pier fancy eating' is the wordplay.
'circling' is an insertion indicator (circling can mean going around or containing).
'end of' indicates one should take the final letters.
'fancy' indicates an anagram.
The last letter of 'pier' is 'r'.
'eating' with letters rearranged gives 'ganite'.
'r' going within 'ganite' is 'GRANITE'.
(Other definitions for granite that I've seen before include "Igneous rock, generally composed of feldspar and mica and quartz" , "Resilience; stone" , "Constituent in Dartmoor" , "Hard stone from Tangier" , "Hard igneous rock" .)