55 Cancri e was first identified back in 2004, but at the time scientists thought that it was covered in water and rocks, much like the Earth. We now know that's probably not true and, what's more, the most interesting find regarding 55 Cancri e could be under the surface.
More accurate measurements have revealed a surface temperature of nearly 4,000 °F, and a density much higher than our planet, leading researchers to conclude that 55 Cancri e is actually composed almost entirely from high-density carbon, or, in other words, solid diamond.
With a diameter that's about double that of earth's, 55 Cancri e revolves around a star called 55 Cancri a. The star is part of the constellation Cancer and is visible from earth with the naked eye, although the much smaller planet is a tough catch. Both are approximately 40 light years from earth, so the chances of heading up there to grab some diamonds are pretty slim.