Stay with them, maybe, and find a gemstone (8)
I believe the answer is:
amethyst
'a gemstone' is the definition.
(amethyst is a kind of gemstone)
'stay with them maybe' is the wordplay.
'with' means one lot of letters go next to another.
'maybe' indicates anagramming the letters.
'stay' put after 'them' is 'themstay'.
'themstay' with letters rearranged gives 'AMETHYST'.
'and find' is the link.
(Other definitions for amethyst that I've seen before include "Violet gemstone" , "Transparent bluish quartz" , "rock" , "A Middle East language" , "Purple gem" .)