Philip Arnold
Philip Arnold | |
|---|---|
| Born | circa 1829 Elizabethtown, Kentucky, U.S. |
| Died | 1878 |
| Occupation(s) | Confidence trickster, prospector, banker |
| Known for | Masterminding the diamond hoax of 1872 |
Philip Arnold (circa 1829–1878) was an American confidence trickster originating from Elizabethtown, Kentucky, notorious for masterminding the diamond hoax of 1872, a deceptive diamond mining venture that earned him more than $500,000.
Biography
Initially, Arnold worked as an apprentice in hat-making with limited formal education before enlisting in the Mexican–American War. He later participated in the 1849 Gold Rush in California, where he achieved sufficient success to return to Kentucky, acquire farmland, marry, and establish a family.
By 1870, Arnold had resumed prospecting and mining in the western territories. Together with his cousin John Slack, he obtained industrial-quality diamonds from James B. Cooper of the Diamond Drill Company and combined them with garnets, rubies, and sapphires purchased from Arizona Native Americans.
They persuaded local entrepreneur George D. Roberts that they had uncovered a new diamond deposit, convincing him to keep the discovery confidential and safeguard the gems. Roberts subsequently involved investors such as William C. Ralston, founder of the Bank of California, Asbury Harpending, William Lent, and General George S. Dodge. This consortium paid Arnold and Slack an initial $50,000 to acquire their rights.
Arnold utilized these funds to procure additional uncut gemstones in England valued at approximately $20,000, some of which were shipped to San Francisco to reinforce the illusion. Meanwhile, Ralston’s group forwarded samples to New York where jeweler Charles Lewis Tiffany appraised them at $150,000—significantly above Arnold’s actual expenses—helping to attract high-profile investors including George B. McClellan, Congressman Benjamin Franklin Butler, and Horace Greeley.
This valuation generated an additional $100,000 for Arnold, who returned to London to buy more uncut stones worth $8,000 to sustain investor enthusiasm.
When investors requested a visit to the source site, Arnold and Slack planted gems at a remote location in northwestern Colorado Territory. In June 1872, they guided investors on a confusing four-day horseback expedition from St. Louis to a site near Rawlins, Wyoming. There, the group discovered an abundance of precious stones and paid Arnold $450,000 for full ownership rights.
The fraud was exposed in October 1872 when the United States Department of the Interior sent Yale geologist Clarence King to examine the site. King detected inconsistencies in the geological conditions necessary for such stones’ formation, revealing the deception to investors including Ralston.
Arnold invested his earnings in real estate near Elizabethtown—purchasing a brick home and 500 acres under his wife Mary’s name—and entered banking by acquiring a defunct local bank in 1873. His professional life ended following a violent altercation with another banker in 1878; Arnold suffered a shotgun injury and died six months later from pneumonia at age 49.
John Slack passed away in New Mexico in 1896.
Legacies
The 1955 Death Valley Days episode titled A Killing in Diamonds portrayed this scam, with Arnold played by Michael Vallon. The series revisited the hoax again in its 1968 episode "The Great Diamond Mines," featuring Gavin MacLeod as Arnold alongside John Fiedler and Tod Andrews.
Arnold’s home from 1872 until his death in 1879, known as the Philip Arnold House located in Elizabethtown, is listed on the National Register of Historic Places.
Additional resources
- Plazak, Dan A hole in the ground with a liar at the top: fraud and deceit in the golden age of American mining (2006) University of Utah Press, 374 pages (features a chapter dedicated to the infamous diamond hoax)
- Wilson, Robert The Explorer King: Adventure, Science, and the Great Diamond Hoax : Clarence King in the Old West (2006), Scribner, New York, NY, 303 pages (a biography emphasizing King's role in uncovering the hoax)