What could make oldie Tom rock (8)
I believe the answer is:
dolomite
'rock' is the definition.
(I know that dolomite is a type of rock)
'what could make oldie tom' is the wordplay.
'what could make' indicates an anagram.
'oldie'+'tom'='oldietom'
'oldietom' with letters rearranged gives 'DOLOMITE'.
(Other definitions for dolomite that I've seen before include "stone" , "Form of rock" , "Limestone rock" , "Mineral after which a range of Italian Alps is named" .)