Playing marble (5)
'playing marble' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for agate that I've seen before include "Hard stone with concentric bands of colour" , "Quartz variety" , "Ornamental form of quartz" , "Quartz with bands of colour, used in jewellery" , "rock with bands" .)
'playing marble' is the definition.
(I've seen this in another clue)
This is the entire clue.