Exodus 28:6-10

6and they shall make the ephod of gold and blue, purple, and scarlet fabric and fine twisted linen, skillfully woven and [beautifully] worked.

7It is to have two shoulder pieces joined to its two [back and front] ends, so that it may be joined together.

8And the skillfully woven sash, which is on the ephod shall be made of the same material: of gold, of blue, purple, and scarlet fabric and fine twisted linen.

9You shall take two onyx stones and engrave on them the names of the [twelve] sons of Israel,

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