Gemstone in ring shown by New York Times (4)
I believe the answer is:
onyx
'gemstone' is the definition.
(onyx is a kind of gemstone)
'ring shown by new york times' is the wordplay.
'ring' becomes 'o'.
'shown by' means one lot of letters go next to another.
'new york' becomes 'ny'.
'times' becomes 'x' (multiplication sign).
'o'+'ny'+'x'='ONYX'
'in' is the link.
(Other definitions for onyx that I've seen before include "Striped agate" , "Agate with different layers of colour" , "Stone-like marble with coloured layers" , "Agate with alternating bands of colour" , "Stone-like marble with layered colours" .)