Exodus 28:9-11

9And thou shalt take two onyx stones, and engrave on them the names of the children of Israel: 10Six of their names on one stone, and the six names of the rest on the other stone, according to their birth. 11With the work of an engraver in stone, like the engravings of a signet, shalt thou engrave the two stones with the names of the children of Israel: thou shalt make them to be set in settings of gold.