Exodus 28:9-12

You shall take two onyx stones and engrave on them the names of the [twelve] sons of Israel, six of their names on one stone and the remaining six names on the other stone, arranged in the order of their births. With the work of a jeweler, like the engravings of a signet, you shall engrave the two stones according to the names of the sons of Israel. You shall have them set in filigree [settings] of gold. You shall put the two stones on the [two] shoulder pieces of the ephod [of the high priest], as memorial stones for Israel; and Aaron shall bear their names on his two shoulders as a memorial before the LORD.