What is the origin of the concept of Yerushalayim being a "City of Gold"?
It is the name and theme of a famous Israeli song from the 1960s, and I always assumed it was either from that song, or that the song was based on an Israeli cultural idea, or possibly an older idea, possibly predating modern Zionism, that (I assumed) stemmed from the Dome of the Rock being so prominent and reflecting a golden light at sunrises and sunsets. At least, I assumed, it was 45 years old. At most, I assumed, it was about 1300 years old. Most likely, I figured, it was somewhere in between. But it's mentioned in the Gemara (Bab. Shab. 59a), which predates Islam by several centuries, and which further cites it mentioned by Rabbi 'Akiva in a Baraitha, several hundred years older than the Gemara itself. What is the origin of this concept?
This question is part of the (struggling) Daf Yomi Challenge