Carnelian
Carnelian takes a crisp engraving and does not stick to hot wax, which made it the material of choice for signet rings across Mesopotamia, Egypt, Greece and Rome. That single practical property is the reason it survives in such quantity.
Egyptian funerary practice associated the stone's colour with vitality, and carnelian amulets appear routinely in burials of the New Kingdom.
The colour is iron oxide within microcrystalline quartz, and much commercial carnelian is heat-treated agate, a practice at least as old as the Roman trade.