Powder that is rarely expensive? (4,4)
I believe the answer is:
gold dust
'powder' is the definition.
(I have seen 'Precious powder' mean 'gold dust' so perhaps 'powder' could also mean 'gold dust')
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for gold dust that I've seen before include "Something valuable (and very rare?)" , "Proverbially rare stuff" , "something much sought-after" , "Fine powder of precious metal" .)