United States dollar (USD) : Symbol: $ and also use in the form of US$. Currency code: USD. The U.S. dollar as a currency is sometimes referred to as the greenback, bucks. The official currency of the United States and its territories per the Coinage Act of 1792. The latest forms of paper money being the Federal Reserve Note that was authorized by the Federal Reserve Act of 1913 while all existing U.S. currency remains legal tender. Since the convertibility of paper U.S. currency into any precious metal was suspended in 1971, the U.S. dollar is de facto fiat money.
Spot Gold (XAU/USD) : XAU refers to the ISO 4217 standard code for one troy ounce of pure gold (99.99%, 24K gold). 24k gold means that all 24 parts in the gold are all pure gold without traces of any other metals. 1 troy ounce (oz t) = 31.1034768 grams. Gold has been usded as real money throughout the world.