Exodus 28:9 in the World English Bible
You shall take two onyx stones, and engrave on them the names of the children of Israel.
Context
8 And the curious girdle of the ephod, which is upon it, shall be of the same, according to the work thereof; even of gold, of blue, and purple, and scarlet, and fine twined linen.
9 And thou shalt take two onyx stones, and grave on them the names of the children of Israel:
10 Six of their names on one stone, and the other six names of the rest on the other stone, according to their birth.