“You shall make a breastplate of judgment, in skilled work. You shall make it in the style of the ephod. You shall make it of gold, of blue and purple and crimson yarns, and fine twined linen. It shall be square and doubled a span in length and a span in width. You shall set in it four rows of stones. A row of carnelian, chrysolite, and emerald shall be the first row. The second row is a turquoise, a sapphire, and a moonstone. The third row is a jacinth, an agate, and an amethyst. The fourth row is a beryl, an onyx, and a jasper. They shall be set in gold filigree. There shall be twelve stones with names according to the names of the sons of Israel. They shall be like signets, each engraved with its name, for the twelve tribes. You shall make for the breastplate chains of pure gold, twisted like cords. You shall make for the breastplate two rings of gold, and put the two rings on the two edges of the breastplate. You shall put the two cords of gold in the two rings at the edges of the breastplate. The two ends of the two cords you shall attach to the two settings. Attach it in front to the shoulder-pieces of the ephod. You shall make two rings of gold, and put them at the two ends of the breastplate, on its inside edge next to the ephod. You shall make two rings of gold, and attach them in front to the lower part of the two shoulder-pieces of the ephod, at its joining above the decorated band of the ephod. The breastplate shall be bound by its rings to the rings of the ephod with a blue cord, so that it may lie on the decorated band of the ephod, and so that the breastplate shall not come loose from the ephod. So Aaron shall bear the names of the sons of Israel in the breastplate of judgment on his heart, when he goes into the holy place, for a continual remembrance before Yahweh. In the breastplate of judgment you shall put the Urim and the Thummim. They shall be upon Aaron’s heart, when he goes in before Yahweh. Thus Aaron shall bear the judgment of the Israelites upon his heart before Yahweh continually.”
The breastplate is made in the style of the ephod, but it is square with 4 rows of 3 stones each. They really knew the various gemstones. 4 rows with 3 stones each corresponds to the 12 tribes of Israel. Of course, there are gold rings at the two ends of the breastplate in order to attach it to the ephod with a blue cord. There is a mention of the Urim and Thummim. These were sacred oracles, in the pouch of the breastplate of judgment. Aaron bears the names of the Israelites and the judgment of the Israelites, when he goes into the holy place, for a continual remembrance.