Revelation 21:18: And the building of the wall of it was of jasper: and the city was pure gold, like unto clear glass.

Revelation 21:18-21 describes the glory of the entire celestial kingdom based on the symbolic building materials used to construct the celestial city of holy Jerusalem.¹ John identifies Jasper as the stone used to build the wall.² Jasper was the most precious of all stones in the ancient world.³ It symbolizes the glory of God.⁴ Thus, the wall of jasper shows that God's glory surrounds the celestial city and her inhabitants.⁵ Since jasper is also exceedingly hard and durable,⁶ this material signifies the enduring and eternal nature of the celestial city.⁷

The celestial city defies all description.⁸ It is built entirely of pure gold that is also paradoxically transparent⁹ and like unto clear glass.¹⁰ The gold symbolizes the spiritual and physical purity of the celestial city¹¹ that will never tarnish.¹² This solid gold city is the mirror opposite image of the golden city of Modern Babylon,¹³ that is corruptible and has only the hypocritical appearance of gold.¹⁴ The celestial city is also transparent to symbolically describe the glory of the celestialized earth¹⁵ when it is rolled back into the presence of God during its resurrection.¹⁶ At that time, as stated in Doctrine and Covenants Section 130:9, "this earth, in its sanctified and immortal state will be made like unto crystal¹⁷ and will be a Urim and Thummim to the inhabitants who dwell thereon."¹⁸

Anciently, the Urim and Thummim, which means lights and perfections¹⁹ consisted of two seer stones used for receiving revelation²⁰ and interpreting languages.²¹ A Urim and Thummim accompanied the gold plates that were buried in the Hill Cumorah,²² which Joseph Smith used to translate the Book of Mormon.²³ Joseph also received revelations and latter-day scripture through the Urim and Thummim²⁴ until he returned the device to the angel Moroni with the gold plates.²⁵

The earth will become a great Urim and Thummim in the future,²⁶ which means it will become a concentration of pure intelligence.²⁷ Celestial people on the earth will be able to gaze into the crystal earth and see all things past, present, and future,²⁸ including all things pertaining to inferior kingdoms.²⁹ Exalted saints in the celestial kingdom will also receive a white stone with a new name³⁰ that will allow them to see kingdoms of a higher order.³¹

Revelation 21:19-20: And the foundations of the wall of the city were garnished with all manner of precious stones. The first foundation was jasper; the second, sapphire; the third, a chalcedony; the fourth, an emerald; The fifth, sardonyx; the sixth, sardius; the seventh, chrysolite; the eighth, beryl; the ninth, a topaz; the tenth, a chrysoprasus; the eleventh, a jacinth; the twelfth, an amethyst.

In John's vision, the foundations of the wall of the city are built from,³² and garnished with all manner of precious stones.³³ The foundation stones are similar to the twelve stones in the breastplate of the High Priest in ancient Israel, which represented the twelve tribes of Israel.³⁴ The foundation stones also represent the divine attributes of the twelve tribes of Israel.³⁵ The twelve foundation stones are apparently visible to John's view because the glorified earth is transparent like crystal.³⁶

The foundation stones are arranged in a specific order because the celestial city is a house of order.³⁷ They are also grouped into four sets of three (4x3) stones each,³⁸ as follows: (1) jasper,³⁹ sapphire,⁴⁰and chalcedony,⁴¹ (2) emerald,⁴² sardonyx,⁴³ and sardius,⁴⁴ (3) chrysolite,⁴⁵ beryl,⁴⁶ and topaz,⁴⁷ and (4) chrysoprasus,⁴⁸ jacinth,⁴⁹ and amethyst.⁵⁰

Revelation 21:21: 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.

The twelve gates with twelve pearls are the proverbial pearly gates used to describe the entrance of heaven.⁵¹ Each gate miraculously consists of a single valuable pearl⁵² of impossible size and luster by earthly standards.⁵³ This imagery corresponds to the Savior's parable of a merchantman who sold all he possessed to obtain the one pearl of great price.⁵⁴ Other teachings by the Savior emphasize the great value of pearls that must not be cast before swine.⁵⁵ The luster of the pearly gates in John's vision is like unto circling flames of fire in Joseph's Smith's vision of the heavenly gate in Doctrine and Covenants Section 137:2.⁵⁶

The street of the city was pure gold, including multiple streets, buildings, and open spaces.⁵⁷ All were made of gold, but they were miraculously like transparent glass.⁵⁸ John describes the beauty of the celestial city in great detail to emphasize that all who enter the city will inherit everything he describes.⁵⁹