White stone in lake rolled back onto flower (9)
I believe the answer is:
alabaster
'white stone' is the definition.
(I've seen this before)
'lake rolled back onto flower' is the wordplay.
'lake' becomes 'Bala' (Lake Bala is a Welsh lake).
'rolled back' says the letters should be written in reverse.
'onto' means one lot of letters go next to another.
'flower' becomes 'aster' (type of flower).
'bala' in reverse letter order is 'alab'.
'alab'+'aster'='ALABASTER'
'in' is the link.
(Other definitions for alabaster that I've seen before include "Form of gypsum used for carving" , "Altar base (anag)" , "Material for sculpting" , "Sculptors work with this" , "Translucent white gypsum as found carved into ornaments" .)