Some metal creates fine powder (4)
I believe the answer is:
talc
'fine powder' is the definition.
(I've seen this before)
'some metal creates' is the wordplay.
'some' indicates the answer is hidden within the clue (some of the parts of the word are used).
'TALC' can be found hidden inside 'metal creates'.
(Other definitions for talc that I've seen before include "Perfumed drying powder" , "Bathroom powder (abbr)" , "Powder used as toiletry" , "Cosmetic powder" , "Softest substance in Mohs scale of hardness" .)