Onyx is a charcoal-coloured gemstone used for jewellery and carving, commonly cut into beads or cabochons. Its contrasting bands also suit cameo engraving. Some is natural, but much of the material traded under the name is stained agate.
Onyx is a charcoal-coloured gemstone used for jewellery and carving, commonly cut into beads or cabochons. Its contrasting bands also suit cameo engraving. Some is natural, but much of the material traded under the name is stained agate.