Lead source of wind starts to nip away (6)
I believe the answer is:
galena
'lead source' is the definition.
(I've seen this in another clue)
'wind starts to nip away' is the wordplay.
'wind' becomes 'gale' (gale is a kind of wind).
'starts to' indicates taking the first letters.
The initial letters of 'nip away' is 'na'.
'gale'+'na'='GALENA'
'of' is the link.
(Other definitions for galena that I've seen before include "Len, GAA produces lead sulphide" , "Angela (anag) - ore producing lead" , "Lead sulphide mineral" , "Commonest ore of lead - Angle "A" (anag)" .)