Minted due to the California Gold Rush, the 1849 Double Eagle was a new, larger $20 gold denomination compared to the old $10 Eagle.
Only 1 example was produced of the 1849 Double Eagle design. It's now housed at the Smithsonian Institution's National Numismatic Collection.
As a pattern coin intended for testing, the 1849 Double Eagle is extremely rare and valuable - worth over $18 million by estimates.
Featuring a left-facing Liberty Head design by James B. Longacre, the obverse is similar to other mid-19th century US gold coins.
Graded Specimen-66, the 1849 Double Eagle at the Smithsonian is in exceptional condition adding to its immense rarity and value.
If the Smithsonian's 1849 Double Eagle was ever sold privately, experts estimate its value would be $18-20 million - making it the world's most valuable coin.
With the California Gold Rush causing the need for heavier denominated coins, the 1849 Double Eagle has special historical significance.