It's Out There: A Planet Made of Diamond Astronomers say '55 Cancri e' has an interesting makeup By John Johnson, Newser Staff Posted Oct 11, 2012 2:35 PM CDT 6 comments Comments (Shutterstock) (Newser) – It's going to need a much better name. A planet known as "55 Cancri e" is making headlines today after astronomers revealed that much of it is made of diamond, reports Space.com. The bad news for ambitious space travelers is that it's 230 trillion miles away and too hot for life, reports Reuters. The planet is about twice the size of our own and also orbits a sun, or something like it. "This is our first glimpse of a rocky world with a fundamentally different chemistry from Earth," says a Yale researcher. "The surface of this planet is likely covered in graphite and diamond rather than water and granite."