Stone with bands a European label backed (5)
I believe the answer is:
agate
'stone with bands' is the definition.
'a european label backed' is the wordplay.
'european' becomes 'e' (abbreviation e.g. EU).
'label' becomes 'tag' ('tag' can be a synonym of 'label').
'backed' says the letters should be written in reverse.
'e'+'tag'='etag'
'etag' reversed gives 'gate'.
'a'+'gate'='AGATE'
(Other definitions for agate that I've seen before include "marble" , "Impure form of quartz with banded chalcedony, used as a gemstone" , "Quartz with bands of colour, used in jewellery" , "Striped stone" , "Old drama critic" .)