Not mad about silver in great demand? (3,3,4)
I believe the answer is:
all the rage
'great demand?' is the definition.
The definition suggests a singular noun which matches the answer.
'not mad about silver' is the wordplay.
'not mad' becomes 'allthere' (I've seen this in other clues).
'about' indicates putting letters inside.
'silver' becomes 'Ag' (Ag is the chemical symbol for silver).
'allthere' going around 'ag' is 'ALL THE RAGE'.
'in' is the link.
Can you help me to learn more?
(Other definitions for all the rage that I've seen before include "The in thing" , "Fashionable" , "Very popular (informal)" , "ultra-fashionable" , "Extremely popular" .)