"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 city walls are described in detail in verses Revelation 21:17, 19-20. The above site gives more information about the other precious jewels stated.
"I did not see a temple in the city, because the Lord God Almighty and the Lamb are its temple. The city does not need the sun or the moon to shine on it, for the glory of God gives it light, and the Lamb is its lamp."
Taken directly from my Life Application Bible...
"The Holy City, the new Jerusalem is described as the place where God will wipe every tear from our eyes...there will be no death, pain, sorrow, or crying."