Done in mosaic (5)
I believe the answer is:
tiled
'done in mosaic' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for tiled that I've seen before include "Covered eg as walls of shower area" , "Covered in pottery slabs" , "Covered or floored with baked clay" , "with a glazed look" , "covered bathroom wall?" .)