Tough, unfinished ring with shiny mineral found in Alabama is heavenly (12)
I believe the answer is:
astronomical
'heavenly' is the definition.
(thesaurus)
'tough unfinished ring with shiny mineral found in alabama' is the wordplay.
I cannot quite understand how this works, but
'ring' could be 'o' and 'o' is located in the answer.
'mineral' could be 'mica' (mica is a kind of mineral) and 'mica' is found in the answer.
This may be the basis of clue (or it may be nonsense).
'is' is the link.
Can you help me to learn more?
(Other definitions for astronomical that I've seen before include "Really, really big" , "Inconceivably large" , "Tremendous" , "Of the study of stars" , "Absolutely huge, in a heavenly way" .)