The U.S. Mint issued its first gold coins in 1795. During the height of the Great Depression in 1933, President Roosevelt made it illegal for American citizens to have gold. He ordered all gold coins be returned to the U.S. Treasury, where millions were melted into gold bars.
These recalls and meltdowns resulted in the previously common gold coins becoming very rare. Today, the surviving pre-1933 U.S. gold coins are fixed at an extremely limited supply.