Mineral adhesive fixing agent recalled (6)
I believe the answer is:
gypsum
'mineral' is the definition.
(gypsum is a kind of mineral)
'adhesive fixing agent recalled' is the wordplay.
'adhesive' becomes 'gum' (gum is a kind of adhesive).
'fixing' is an insertion indicator (inserted letters are fixed inside others).
'agent' becomes 'spy' (spy is a kind of agent).
'recalled' says the letters should be written in reverse.
'spy' back-to-front is 'yps'.
'gum' enclosing 'yps' is 'GYPSUM'.
(Other definitions for gypsum that I've seen before include "Mineral used to make plaster of Paris" , "Ingredient of fertilizer" , "Alabaster" , "Plaster of Paris is made from this chalk-like substance" , "Mineral used in making plaster of Paris" .)