Exodus 28:9-12

9“You are to take two onyx stones and engrave on them the names of Bnei-Yisrael:

10six of their names on one stone and the names of the remaining six on the other stone, in the order of their birth.

11With the work of a gem cutter engraving a seal, etch the two stones, in the order of the names of Bnei-Yisrael. Make them enclosed in settings of gold.

12Fasten the two stones upon the shoulder pieces of the ephod, to be memorial stones for Bnei-Yisrael. So Aaron is to bear their names before Adonai on his two shoulders as a reminder.