As a jeweler engraves signets, so shall you engrave the two stones with the names of the sons of Israel. You shall enclose them in settings of gold filigree.
Directions are here given concerning the ephod, which was the outmost garment of the high priest. Linen ephods were worn by the inferior priests, Sa1 22:18. Samuel wore one when he was a child (Sa1 2:18), and David when he danced before the ark (Sa2 6:14); but this which the high priest only wore was called a golden ephod, because there was a great deal of gold woven into it.
Commenting on Exodus 28:6-14
With the work of an engraver in stone,.... Not in common but precious stones: Moses was not to do this himself, as it could not be supposed he should, but he was to employ an engraver, whose business it was, and one that was capable of doing it in a professional manner: like the engravings of a signet shall thou engrave the two stones with...
Like the engravings of a signet - So signets or seals were in use at this time, and engraving on precious stones was then an art, and this art, which was one of the most elegant and ornamental, was carried in ancient times to a very high pitch of perfection, and particularly among the ancient Greeks; such a pitch of perfection as has never been...