Granite's disintegrating; it's not chemically reactive (5,3)
I believe the answer is:
inert gas
'not chemically reactive' is the definition.
I can't judge whether this defines the answer.
'granite's disintegrating' is the wordplay.
'disintegrating' indicates anagramming the letters (I've seen 'disintegrated' mean this).
'granites' is an anagram of 'INERT GAS'.
'it's' acts as a link.
Can you help me to learn more?
(Other definitions for inert gas that I've seen before include "provokes no reaction" , "one at the edge of a table" , "Such as neon or xenon" , "One expects no reaction from such" , "He perhaps" .)