There are 15 specimens of the <a href="https://en.wikipedia.org/wiki/1804_dollar" class="extiw" title="w:1804 dollar">1804 dollar</a> known to exist (seven of which are in museum collections). Despite the date on the coin, none of them were struck before the 1830s. The Class III example pictured (based on the lettering used on the coin) is one of only six known, and may have been struck as late as the 1850s. It sold in a 2009 auction for USD $2,300,000.
<a href="https://en.wikipedia.org/wiki/United_States_Mint" class="extiw" title="w:United States Mint">United States Mint</a> (coin); Heritage Auctions (image)
Heritage <a rel="nofollow" class="external text" href="https://coins.ha.com/itm/early-dollars/silver-and-related-dollars/1804-1-class-iii-pr58-pcgs/a/1124-2567.s">Lot 2567</a>, 30 April 2009