Gem used in intaglio (4)
I believe the answer is:
onyx
(Other definitions for onyx that I've seen before include "African antelope" , "Stone-like marble with layered colours" , "Type of agate" , "material for making cameos" , "Cameo material" .)
I believe the answer is:
onyx
(Other definitions for onyx that I've seen before include "African antelope" , "Stone-like marble with layered colours" , "Type of agate" , "material for making cameos" , "Cameo material" .)