A handful of city homes now listed for sale or rent include unusual built-in elements made from gold, crystals, even marble once favored by the ancient Romans. A look at them — and more — below.

With a $3 billion price tag, the Emirates Palace in Abu Dhabi was said to be the most expensive hotel to have been built when it opened in 2005. Its hallways, rooms and lobbies feature more than 1,000 ...