Revelation 21:17-21

17  And he measured the wall thereof, an hundred and forty and four cubits, according to the measure of a man, that is, of the angel.

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

19  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;

20  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.

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.

Johns gives further description of the holy city. It is breathtaking in beauty. There are twelve foundation colors of jewels and the foundations themselves are garnished with all types of precious stones. The city itself is made of clear gold glass crystal and so are the streets. Each gate is made out of a single pearl. Some of these colors mentioned have changed in meaning over the years so we cannot be certain about all the actual colors.