China core thrown with simple exterior (9)
I believe the answer is:
porcelain
'china' is the definition.
(I've seen this before)
'core thrown with simple exterior' is the wordplay.
'thrown' is an anagram indicator.
'with simple' becomes 'plain' (associated in meaning. I am not sure about the 'with' bit.).
'exterior' means one lot of letters goes inside another (some letters go on the outside of others).
'core' is an anagram of 'orce'.
'orce' inserted inside 'plain' is 'PORCELAIN'.
Can you help me to learn more?
(Other definitions for porcelain that I've seen before include "Fine ceramic ware" , "Crockery" , "Fine white ceramic" , "Form of ceramic" , "Fine white China" .)