Dark gem (4)
I believe the answer is:
onyx
(Other definitions for onyx that I've seen before include "Semi-precious stone used in making cameos" , "Stones" , "Black variety of quartz" , "Form of quartz" , "Hard stone with coloured layers" .)
I believe the answer is:
onyx
(Other definitions for onyx that I've seen before include "Semi-precious stone used in making cameos" , "Stones" , "Black variety of quartz" , "Form of quartz" , "Hard stone with coloured layers" .)