Jewel with tip of ruby set in ring (5)
I believe the answer is:
pearl
'jewel' is the definition.
(pearl is a kind of jewel)
'tip of ruby set in ring' is the wordplay.
'tip of' suggests taking the first letters.
'set in' is an insertion indicator.
'ring' becomes 'peal' ('peal' can be a synonym of 'ring'**).
The first letter of 'ruby' is 'r'.
'r' put into 'peal' is 'PEARL'.
'with' acts as a link.
(Other definitions for pearl that I've seen before include "Gem from the sea" , "greatly valued" , "Lustrous structure in a mollusc shell" , "finest example" , "one regularly in stitches" .)