Sculptures are a blast in mineral (9)
I believe the answer is:
alabaster
'mineral' is the definition.
(alabaster is a kind of mineral)
'sculptures are a blast' is the wordplay.
'sculptures' is an anagram indicator (I've seen 'sculpture' mean this).
'are a' becomes 'area' (maths abbreviation).
'area'+'blast'='areablast'
'areablast' anagrammed gives 'ALABASTER'.
'in' acts as a link.
(Other definitions for alabaster that I've seen before include "Carved form of gypsum" , "Form of gypsum used for carving" , "Material for sculpting" , "White mineral used for carving" , "Altar base (anagr.)" .)