Exodus 39:7-9

Amplified Bible

⁷ And he put them on the shoulder pieces of the ephod to be memorial stones (a remembrance) for the sons of Israel (Jacob), just as the Lord had commanded Moses.

⁸ Bezalel made the breastpiece, the work of a skillful craftsman, like the workmanship of the ephod: of gold and of blue, purple, and scarlet fabric, and fine twisted linen. ⁹ It was square; they made the breastpiece folded double, a [hand’s] span long and a [hand’s] span wide when folded double.