“And the twelve gates were twelve pearls; every several gate was of one pearl: and the street of the city was pure gold, as it were transparent glass.”
King James Version (KJV)
21:19 And the foundations were adorned with precious stones - That is, beautifully made of them. The precious stones on the high priest's breastplate of judgment were a proper emblem to express the happiness of God's church in his presence with them, and in the blessing of his protection. The like ornaments on the foundations of the walls of this city may express the perfect glory and happiness of all the inhabitants of it from the most glorious presence and protection of God. Each precious stone was not the ornament of the foundation, but the foundation itself. The colours of these are remarkably mixed. A jasper is of the colour of white marble, with a light shade of green and of red; a sapphire is of a sky - blue, speckled with gold; a chalcedony, or carbuncle, of the colour of red - hot iron; an emerald, of a grass green.
21:20 A sardonyx is red streaked with white; a sardius, of a deep red; a chrysolite, of a deep yellow; a beryl, sea - green; a topaz, pale yellow; a chrysoprase is greenish and transparent, with gold specks; a jacinth, of a red purple; an amethyst, violet purple.
21:22 The Lord God and the Lamb are the temple of it - He fills the new heaven and the new earth. He surrounds the city and sanctifies it, and all that are therein. He is all in all.
21:23 The glory of God - Infinitely brighter than the shining of the sun.
Re 21:21 The twelve gates [were] twelve pearls. Each gate composed of a single pearl. The street of the city [was] pure gold. The streets were paved with pure gold. As it were transparent glass. Transparency is the symbol of purity.