Exodus 28:10

8And 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.

9And thou shalt take two onyx stones, and grave on them the names of the children of Israel:

10Six of their names on one stone, and the other 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 ouches of gold.

12And thou shalt put the two stones upon the shoulders of the ephod for stones of memorial unto the children of Israel: and Aaron shall bear their names before the LORD upon his two shoulders for a memorial.