The wall was made of jasper, and the city of pure gold, as pure as glass. The foundations of the city walls were decorated with every kind of precious stone. The first foundation was jasper, the second sapphire, the third chalcedony, the fourth emerald, the fifth sardonyx, the sixth carnelian, the seventh chrysolite, the eighth beryl, the ninth topaz, the tenth chrysoprase, the eleventh jacinth, and the twelfth amethyst. The twelve gates were twelve pearls, each gate made of a single pearl. The great street of the city was of pure gold, like transparent glass. Revelation 21:18-21
This could be an accurate, literal description of the materials
used in heaven or an author’s creative description (using metaphors and
similes) of what heaven is like.
Either is fine.
The author, the apostle John, wanted to communicate something more
than just dimensions and building codes, but beauty, awe and splendor.
The most precious items on earth (gold, jewels, crystals) are essentially
in heaven mere construction materials (like wood, brick or concrete).
Earth’s most valuable stones do not compare to the value of God
Himself. In contrast to Him in heaven, they are worth nothing.
We are amazed that God would create such a place for us, with no
shortcuts or cost-saving methods, but with all the splendor earth could buy.