article_snippet: A rare five-dollar gold piece .
article_snippet: and a prized silver dollar each could fetch $10 million or more .
article_snippet: Above, a rare 1822 Half Eagle five-dollar gold piece, one of only three known to exist.
article_snippet: Above, a rare 1822 Half Eagle five-dollar gold piece, one of only three known to exist each could fetch $10 million or more in upcoming auctions .
article_snippet: An 1822 Half Eagle five-dollar gold piece, one of only three .