Exodus 28:17-21

Then mount four rows of precious stones on it. The first row shall be carnelian, chrysolite and beryl; the second row shall be turquoise, lapis lazuli and emerald; the third row shall be jacinth, agate and amethyst; the fourth row shall be topaz, onyx and jasper. Mount them in gold filigree settings. There are to be twelve stones, one for each of the names of the sons of Israel, each engraved like a seal with the name of one of the twelve tribes.