Using 150k tonnes of above ground gold, if all of it was minted into currency, would equal +- 100M dollars. Probably not more than 10% is minted currency coins - .999 isn't for currency use. So there is about 10M dollars in existence.
5,760,000,000,000 USD, except for the fact that Troy ounces are slightly different than normal ounces. Too lazy to look up.
edit:typo