Illustration shows cross-section view of 55 Cancri e A team of American-Franco researchers led by Yale University have discovered a nearby planet, twice as big as Earth, with a mantle that could be composed largely of diamonds. The planet, known as 55 Cancri e, is located just 40 light years away in the constellation of Cancer and is likely covered in diamond and graphite rather than water and granite,... 

Twinkle, twinkle little star: The diamond planet - the shrunken core of a once-huge star - is a chunk of crystallised carbon measuring 40,000 miles across, five times the diameter of Earth. It is certainly what you could call a gem of a discovery. Astronomers believe they have found an entire planet made of diamonds. Scientists at the University of Manchester think they have unearthed a once-massive...