I don't really care to point out where this was said in the Bible at this point since I'm irritated, I'm just in the mood to say this.

The concept of a "city of gold" is a fallacious play on the physical world's concept of the value placed on gold. Considering gold was used as a "selling point" of "God's riches", it plays a part on giving into greed. A city made of gold is not a necessity, nor does it show for anything other than this world's artificial value placed on gold. There would actually have been no need to use this example, but it was used to persuade people into thinking that a city made of gold would be something to look forward to, but Heaven would have no inherent purpose of gold in the first place, therefore it carries no actual value.

If it was a City of Diamond or a City of Platinum, it would carry the same effect. It was used only to give the illusion of a worth which is artificially and superficially distributed among society. Personally, I'd love a City of Ruby, because that one looks cool, but there is no worth for the City of Ruby other than being used as visually pleasing to me (not to a blind man). If you are placed into an environment where rubies are equivalent to dust, then the "City of Ruby" is worthless.

I wonder what the structural integrity of a City of Gold is like. Let's make it a City of Titanium; I think it would last longer, but I'm not sure.