Precious stone may make them stay (8)
I believe the answer is:
amethyst
'precious stone' is the definition.
(I've seen this before)
'make them stay' is the wordplay.
'make' indicates an anagram.
'them'+'stay'='themstay'
'themstay' with letters rearranged gives 'AMETHYST'.
'may' is the link.
(Other definitions for amethyst that I've seen before include "Bluish-violet 3" , "Type of quartz" , "Purplish gemstone" , "February gemstone" , "Violet-coloured stone" .)