Sparkling silver conveyance (8)
I believe the answer is:
aglitter
'sparkling' is the definition.
('aglitter' can be a synonym of 'sparkling')
'silver conveyance' is the wordplay.
'silver' becomes 'ag' (Ag is the chemical symbol for silver).
'conveyance' becomes 'litter' (litter is a kind of conveyance).
'ag'+'litter'='AGLITTER'
(Other definitions for aglitter that I've seen before include "Shiny" , "Sparkling with light" .)