Brilliant! Stones devoted lyrics after groupie in the wings (6)
I believe the answer is:
geodes
'brilliant stones' is the definition.
'geodes' can be an answer for 'stones' (I've seen this before). I'm not sure about the 'brilliant' bit.
'devoted lyrics after groupie in the wings' is the wordplay.
I cannot really understand how this works, but
'lyrics' could be 'odes' (ode is a kind of lyric) and 'odes' is located in the answer.
The remaining letters 'ge' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for geodes that I've seen before include "Stones" , "Rock cavities lined with crystals - see dog (anag)" .)