Revelation 21:14–21 (NKJV)
After seeing the outside of the city and the gates, the view turns to the foundations, the measurements of the city, and the interior of the city. Its splendor is beyond compare, unlike anything ever seen before.
14 Now the wall of the city had twelve foundations, and on them were the names of the twelve apostles of the Lamb. 15 And he who talked with me had a gold reed to measure the city, its gates, and its wall. 16 The city is laid out as a square; its length is as great as its breadth. And he measured the city with the reed: twelve thousand furlongs. Its length, breadth, and height are equal. 17 Then he measured its wall: one hundred and forty-four cubits, according to the measure of a man, that is, of an angel. 18 The construction of its wall was of jasper; and the city was pure gold, like clear glass.Revelation 21:14-18
The wall of the city, known to be made of a crystal-clear jasper, sits on a twelve-layer foundation. On each foundation was the name of one of the apostles. The narrator had a gold reed with which to measure the city, its gates and its walls. The city is in the shape of a square. Its length and its breadth were equal. When measured with the golden reed, the city was twelve thousand furlongs (about 1380 miles) long, wide, and high. So, beyond the square shape of the city, it was actually a cube as well. The city was 1380 mi x 1380 mi x 1380 mi, or 2.62 x 109 cubic miles. The walls were 216 feet thick (this measurement is in question), and they were made of jasper. The overall appearance of the city was like pure gold, clear as glass. The more pure a substance is, the more translucent it is. The purest gold, like would be in heaven, would have an appearance of being clear.
19 The foundations of the wall of the city were adorned with all kinds of precious stones: the first foundation was jasper, the second sapphire, the third chalcedony, the fourth emerald, 20 the fifth sardonyx, the sixth sardius, the seventh chrysolite, the eighth beryl, the ninth topaz, the tenth chrysoprase, the eleventh jacinth, and the twelfth amethyst.Revelation 21:19-20
The foundations were covered with all types of jewels and precious stones. They were layered with jasper, sapphire, chalcedony, emerald, sardonyx, sardius, chrysolite, beryl, topaz, chrysoprase, jacinth, and amethyst. Pictures of these stones are illustrated below in this blog. The beauty of the stones in colors like green, red, purple, white, and rust present a powerfully opulent look to these foundations.
21 The twelve gates were twelve pearls: each individual gate was of one pearl. And the street of the city was pure gold, like transparent glass.Revelation 21:21
After the description of the size, the walls, and the foundations, the attention turns to the gates to the city. There are twelve gates, and each gate is made of a single pearl. While this seems a bit unseemly, as a giant round pearl would not be usable as a gate, perhaps each gate was carved from one pearl, and served as a gate to the city. The street of the city was pure gold, like a transparent street of glass. The most precious things on earth were now being used as construction material in heaven. Most people do not own much gold, perhaps only ounces. The streets of heaven are paved with it. Not many people own more than a pair of pearl earrings or a string of pearls. The gates of the city (normally wrought iron or wood) are made of a giant pearl. Precious stones are the foundations of the New Jerusalem, normally concrete or blocks on earth. This display of beauty and wealth are unique to a place designed and built by God Almighty.