Temple altar, perhaps, inlaid with sort of nacre (10)
I believe the answer is:
tabernacle
'temple' is the definition.
(thesaurus)
'altar perhaps inlaid with sort of nacre' is the wordplay.
'altar perhaps' becomes 'table' (altar is a kind of table).
'inlaid with' is an insertion indicator.
'sort of' indicates an anagram.
'nacre' anagrammed gives 'ernac'.
'table' placed around 'ernac' is 'TABERNACLE'.
(Other definitions for tabernacle that I've seen before include "A celebrant (anag) - place of worship" , "Portable tent" , "Nonconformist church" , "Place of worship; sacrament box" , "Tent for the Ark of the Covenant" .)