Consumed by silver stone (5)
I believe the answer is:
agate
'stone' is the definition.
(I've seen this before)
'consumed by silver' is the wordplay.
'consumed' becomes 'ate' (to eat is to consume food).
'by' means one lot of letters go next to another.
'silver' becomes 'Ag' (Ag is the chemical symbol for silver).
'ate' after 'ag' is 'AGATE'.
(Other definitions for agate that I've seen before include "Quartz gem" , "Type of quartz" , "Impure form of quartz with banded chalcedony, used as a gemstone" , "Hard stone with concentric bands of colour" , "Striped stone" .)