‘And the building of its wall was jasper, and the city was pure gold like pure glass.'
The jasper is presumably similar to the jasper of Revelation 21:11, clear as crystal which, with the glass-like nature of the city, demonstrates its purity and righteousness. The mention that it is made of gold stresses that it is beyond price and demonstrates its magnificence. Even Solomon's Temple and Herod's Temple pale into insignificance beside it. It again indicates its identity with the inner Sanctuary.