RobH_en_tn/rev/21/18.md

The wall was built of jasper and the city of pure gold

This can be stated in active form. AT: "Someone had built the wall with jasper and the city with pure gold" (See: rc://en/ta/man/translate/figs-activepassive)

pure gold, like clear glass

The gold was so clear that it is spoken of as if it were glass. (See: rc://en/ta/man/translate/figs-simile)

jasper ... emerald ... carnelian

These are valuable stones. Jasper may have been clear like glass or crystal, and carnelian may have been red. Emeralds are green. See how you translated these in Revelation 4:3. (See: rc://en/ta/man/translate/translate-unknown)