Decoration of stone sculpture (7)
I believe the answer is:
festoon
'decoration' is the definition.
(festoon is a kind of decoration)
'of stone sculpture' is the wordplay.
'sculpture' is an anagram indicator.
'of'+'stone'='ofstone'
'ofstone' with letters rearranged gives 'FESTOON'.
(Other definitions for festoon that I've seen before include "Hung garland" , "swag" , "Decorative chain" , "Ornamental garland" , "Decorate with strings of flowers or fabric say" .)