City & wall
The city of New Jerusalem is described as being made of pure gold that is as clear as glass(Rev. 21:18). When we think of gold, we hardly think of it as clear. This means the gold in Heaven is more pure than any on Earth.
The wall surrounding the city is made of jasper(Rev. 21:18). This is not like the jasper we know today that is dark and opaque like these:
The jasper the Apostle John is describing in his vision of Heaven has a brilliance that is as clear as crystal(Rev. 21:11).
Foundation
The city has 12 foundations named after the 12 apostles of Jesus, each decorated with a precious stone(Rev. 21:14). The apostles were the foundation of church Jesus started. As a result, having the foundations of New Jerusalem named after them would be fitting.
The types of stones differ based on versions of the Bible. To those of us who aren’t experts in stones, some are completely unknown. What would they look like? We have no way of knowing for certain what the stones look like as the modern names differ from those of ancient times.
Here’s a summary based on the NIV and KJV versions of the Bible:
| Foundation | NIV | KJV | Color* | Rev. verse |
| 1 | Jasper | Jasper | Unknown | 21:19 |
| 2 | Sapphire | Sapphire |  | 21:19 |
| 3 | Agate | Chalcedony | Unknown | 21:19 |
| 4 | Emerald | Emerald |  | 21:19 |
| 5 | Onyx | Sardonyx |  | 21:20 |
| 6 | Ruby | Sardius |  | 21:20 |
| 7 | Chrysolite | Chrysolite |  | 21:20 |
| 8 | Beryl | Beryl |  | 21:20 |
| 9 | Topaz | Topaz |  | 21:20 |
| 10 | Turquoise | Chrysoprasus |  | 21:20 |
| 11 | Jacinth | Jacinth |  | 21:20 |
| 12 | Amethyst | Amethyst |  | 21:20 |
The first foundation is jasper. Interestingly, jasper is not just what the wall of the city is made out of but is also used to describe the appearance of God sitting on the throne(Rev. 4:3).
Street of gold
The main street of the city is pure gold, also as clear as glass(Rev. 21:21). The gold street is described as “great”, meaning it must be wide and have several lanes. This description implies some kind of advanced transportation in addition to walking.
Is this a literal street of gold? Why not? The foundation stones are named, and the rest of the city is described in vivid detail that would sound strange for it to be figurative.
Unique city
This city is built with the most extravagant building materials. On Earth, gold is very valuable, yet in Heaven it will be considered pavement. No city on Earth is like this or ever will be.
* Walvoord Zuck, The Bible Knowledge series(Zondervan Publishing House), p. 986