Banded gemstone (5)
'banded gemstone' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for onyx that I've seen before include "Form of chalcedony" , "Stone-like marble with different colours in layers" , "Black variety of quartz" , "Quartz with alternating bands of colour" , "Chalcedony agate" .)
'banded gemstone' 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 "Semi-precious quartz" , "Decorative stone" , "Precious stone" , "Semi-transparent stone" , "Onyx" .)