Georgia Deighton has a lead base (6)
I believe the answer is:
galena
'lead base' is the definition.
The answer and definition can be both substances as well as being singular nouns.
Perhaps you can see an association between them that I don't see?
'georgia deighton has a' is the wordplay.
'georgia' becomes 'GA' (abbreviation for the US state).
'deighton' becomes 'len' (I've seen this in another clue).
'has' is a charade indicator (letters next to each other).
'ga'+'len'+'a'='GALENA'
Can you help me to learn more?
(Other definitions for galena that I've seen before include "Lead sulphide mineral" , "Len, GAA produces lead sulphide" , "Angela (anag) - ore producing lead" , "Commonest ore of lead - Angle "A" (anag)" .)