These two phrases mean basically the same thing. The second emphasizes the brilliance of Jerusalem by naming a specific jewel. (See: [[rc://en/ta/man/jit/figs-parallelism]])
This is a valuable stone. Jasper may have been clear like glass or crystal. See how you translated this in [Revelation 4:3](../04/03.md). (See: [[rc://en/ta/man/jit/translate-unknown]])