The adjective diaphanēs means transparent — allowing light to pass through unimpeded. It appears in Revelation 21:21 to describe the streets of the New Jerusalem as pure gold 'like transparent glass,' part of the breathtaking vision of the eternal city where God's glory provides all the light needed.
The New Jerusalem's transparent gold streets represent the ultimate transformation of all earthly value. Gold — the most prized material in human civilization — becomes so purified and glorified in God's presence that it takes on the quality of glass, allowing divine light to pass through it. Nothing in the new creation will impede or diminish God's glory; all material reality will become a medium for His radiance.