The wall of the city also had twelve foundation stones, and on them the twelve names of the twelve apostles of the Lamb.” (Revelation 21:11b-14)

In harmony with this, the foundation stones have on them the names of the 12 apostles of the Lamb. Yes, New Jerusalem is not the fleshly nation of Israel founded on the 12 sons of Jacob. It is the spiritual Israel, founded on “the apostles and prophets.”​—Ephesians 2:20.

The foundations of the city’s wall were adorned with every sort of precious stone: the first foundation was jasper, the second sapphire, the third chalcedony, the fourth emerald, the fifth sardonyx, the sixth sardius, the seventh chrysolite, the eighth beryl, the ninth topaz, the tenth chrysoprase, the eleventh hyacinth, the twelfth amethyst.

Revelation 21:18-

12. What is signified by the fact that (a) the city’s foundations are adorned with 12 precious gems? (b) the city’s gates are pearls?

¹² Even the city’s foundations are beautiful, being adorned with 12 precious gems. This calls to mind the ancient Jewish high priest, who on ceremonial days wore an ephod studded with 12 different precious stones somewhat similar to the ones described here. (Exodus 28:15-21) Surely this is no coincidence! Rather, it emphasizes the priestly function of New Jerusalem, of which Jesus, the great High Priest, is the “lamp.” (Revelation 20:6; 21:23; Hebrews 8:1)