Love friend, providing a precious stone (4)
I believe the answer is:
opal
'a precious stone' is the definition.
(I've seen this before)
'love friend' is the wordplay.
'love' becomes 'o' (In tennis, 'love' means 'zero').
'friend' becomes 'pal' (pal is a kind of friend).
'o'+'pal'='OPAL'
'providing' is the link.
(Other definitions for opal that I've seen before include "Opaque gem" , "Opaque mineral used a gemstone" , "Jewellery item" , "Translucent gemstone" , "precious jewel" .)