One of the rarest and most valuable coins is dubbed the ruby slippers of American coins due to its scarcity. The 1849 Liberty Head Double Eagle is a coin that can never be purchased, because only two are known to exist, and theyre both owned by the US government. This coin owes its existence to the 1849 California Gold Rush.How a Single Discovery at Sutters Mill Triggered Global Gold FeverSutters Mill. Source: Library of CongressIt wasnt long after the Mexican-American War, which resulted in California being ceded to the United States, that gold was discovered in the hills. It was 1848 when James W. Marshall found large quantities of gold at Sutters Mill in the Sierra Nevada Foothills. When the news reached all corners of the country and the world, people were blinded by gold fever. Over 300,000 people flooded California to stake a claim.Inside the Depressing 1840s Economic Crisis That Left the US Desperate for a LifelineSutters Mill. Source: Library of CongressIn the 1840s, the United States was still recovering from the Panic of 1837. There were international and national causes of the panic, including the countrys lack of a central bank to regulate fiscal policy, the acceptance of mixed coinage from multiple countries, the decline in cotton prices, Great Britains refusal to lend money, and the collapse of the land bubble.President Andrew Jackson didnt think the country needed a centralized bank, but he was wrong. The United States economy was doing all right, but it needed a leg up to restore prosperity. When gold was found at Sutters Mill, it injected new life into the American economy.Too Much Gold: Why Congress Was Forced to Invent the $20 Double EaglePresident Andrew Jackson. Source: Library of CongressWith the large influx of gold into the American economy, the demands on Congress were huge. There were such large gold reserves being sent back to the East Coast that Congress was unsure of how to handle the surplus.The 1792 Mint Act had made the $10 gold piece, also known as the eagle, the highest coin denomination in the country. Congress enacted a new law and made $20 gold pieces, or the double eagle. Double eagles would convert the bullion into currency with the least amount of effort. The double eagles also cemented the United States as a geopolitical power on the world stage.The Toxic Mint Sabotage That Nearly Ruined Americas Rarest CoinJames B. Longacre. Source: WikipediaChief Engraver James B. Longacre was tasked with designing the new double eagle. He was a loner at the Philadelphia Mint because the people who worked there were friends and relatives of Director Robert M. Patterson. Longacre struggled with making the double eagle because he was the only person working on the project. When he asked for assistance, he was denied. Chief Coiner Franklin Peale also had beef with Longacre and refused to assist in making the new coin. Peale used the mint tools and facilities to run a personal medal company. Patterson gave Peale permission to harass Longacre.Destroyed Models and Secret Copies: The Lonely Battle to Mint the 1849 Gold Eagle1849 Liberty Double Eagle. Source: PCGSWith the complicit harassment jeopardizing his work at the mint, Longacre was forced to work on nearly all aspects of the double eagle project alone. One example is that he prepared a large model of the coin in wax and gave it to Peale to be placed in galvano-.The project failed, and the wax model was destroyed, but Longacre had made a plaster copy of the model, so he continued his work. He also had trouble casting dies for the double eagle. The first and second attempts failed, followed by a third attempt that was only successful because a friend of Longacre, Charles Cushing Wright, hired an outside engraver to help with the ordeal. By December 1849, the obverse and reverse dies had been made, and it was time to start striking double eagles.Peale was minting the coins, but in the process learned that the relief of the eagle on the reverse was too high to make coins. Peale informed Patterson of the conundrum. The coins couldnt be struck for mass production. With such problems and delays, only a few coins were minted. The majority of the cache of 1849 Liberty Head Gold Eagles was melted, while two were kept. One was sent to the Philadelphia Mint Cabinet, and the second to Secretary of the Treasury W.M. Meredith.One Safe, One Missing: The Unsolved Mystery of the Disappeared Meredith CoinSmithsonian Institute. Source: Library of CongressThe coin from the Philadelphia Mint Cabinet was later transferred to the Smithsonian, where it became a permanent part of the museums rare coin collection. It is currently on display in the Legendary Coins case as part of The Value of Money exhibit. Meanwhile, the Meredith coin has disappeared. There is speculation that it went to the Stephen Nagy collection in Philadelphia in the 1950s, but nothing is confirmed. It is possible that the Meredith coin could reappear one day, or that it is in a private collection the owner wants to keep secret.Even J.P. Morgans Fortune Couldnt Buy This Legendary US CoinJ.P. Morgan. Source: Library of CongressThe coin is so sought after by numismatists that billionaires have gone to extreme lengths to acquire it. The most famous example is that of J.P. Morgan, who offered the United States government $35,000 for the 1849 Liberty Head Double Eagle. The US government, of course, refused.It can be speculated that if the US had sold the double eagle to J.P. Morgan, it would still be in private hands and would be sold for vast sums at various auctions. The Smithsonian, however, keeps the ruby slippers of American numismatics preserved for all time for Americans and other visitors to enjoy.