Philip Arnold was a confidence trickster from Elizabethtown, Kentucky, who was 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. Wikipedia*
On the C-SPAN Networks:
Phillip Arnold has one video in the C-SPAN Video Library; the first appearance was a 1995 House Committee.