A Gran worked with old material (6)
I believe the answer is:
angora
'material' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.
'a gran worked with old' is the wordplay.
'worked with' indicates an anagram.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'gran' anagrammed with 'o' makes 'ngora'.
'a'+'ngora'='ANGORA'
Can you help me to learn more?
(Other definitions for angora that I've seen before include "Soft yarn from certain goats" , "Mohair wool" , "Goat prized for its long silky hair" , "Wool from hair of goats" , "Name of goat at 12 Across" .)