Gold is a fungible commodity, meaning one unit of gold is interchangeable with another unit of gold. Any object made of gold can be smelted and refashioned into something else made of gold. So unless an object retains its original form, once it is smelted, all evidence of its existence is gone. This is why, for instance, gold stolen from Holocaust victims (PDF) was impossible to trace once it was removed and smelted. Many people do not realize that nations today are the largest owners of gold, so it's quite likely some of that gold originated in the New World during the era of European conquest. For instance, the largest owner of gold, the United States as a sovereign nation, owned, as of November 2017, some 8,133 metric tons of gold in bullion form. A metric ton equals 1,000 kilograms or about 2,205 pounds. That means the United States holds about 18 million pounds of gold in vaulted reserves -- approximately 3 percent of all gold ever mined by humans -- in places like Fort Knox and the Federal Reserve Bank of New York.