Precious Stones: Art of Engraving Upon, Early Known to the Jews
Source: TTT
Exodus 28:9, 11, 21
Take two onyx stones and engrave on them the names of the sons of Israel: / Engrave the names of the sons of Israel on the two stones the way a gem cutter engraves a seal. Then mount the stones in gold filigree settings. / The twelve stones are to correspond to the names of the sons of Israel, each engraved like a seal with the name of one of the twelve tribes.