Perhaps one is turned to stone (8)
I believe the answer is:
sapphire
'stone' is the definition.
(thesaurus)
'perhaps one is turned' is the wordplay.
'one' becomes 'i' (Roman numeral).
'is turned' indicates anagramming the letters.
'perhaps'+'i'='perhapsi'
'perhapsi' is an anagram of 'SAPPHIRE'.
'to' is the link.
(Other definitions for sapphire that I've seen before include "Corundum gemstone" , "Deep blue - precious stone" , "precious item" , "Deep blue colour" , "sparkler" .)