Philip Arnold

Philip Arnold (c. 1829–1878) was an American confidence trickster from Elizabethtown, Kentucky, and the brains behind the legendary diamond hoax of 1872, which fooled people into investing in a phony diamond mining operation. He managed to walk away from the hoax with more than half a million dollars.

Biography Arnold was a poorly educated hatter's apprentice when he enlisted to serve in the Mexican–American War. He then went to California as part of the Gold Rush of 1849. He apparently met with some success there, as he was able to return to his native Kentucky, buy a farm, marry, and start a family.

By 1870, he had returned to the West to take a job as a miner and prospector. He and his cousin John Slack obtained some industrial-grade diamonds from their friend James B. Cooper, then an assistant bookkeeper for the Diamond Drill Company of San Francisco. They mixed the diamonds in with garnets, rubies, and sapphires he bought from Indians in Arizona. Concluding that it was a fraud, he quickly traveled to San Francisco to inform Ralston and the other investors, unveiling the Diamond hoax of 1872.

Legacies A 1955 episode of the television series Death Valley Days called A Killing in Diamonds was based on this fraud. Arnold was played by actor Michael Vallon. Death Valley Days aired another story devoted to the hoax, the 1968 episode "The Great Diamond Mines", with Arnold played by Gavin MacLeod, John Slack by John Fiedler, and William Chapman Ralston by Tod Andrews.

The Philip Arnold House in Elizabethtown, where he lived from 1872 to his death in 1879, is listed on the National Register of Historic Places.