Their results suggest 55 Cancri e is largely composed of carbon (in the form of graphite and diamond), iron, silicon carbide, and, potentially, silicates.

BBC: Oddballs: The strange worlds beyond our Solar System

This body, known as 55 Cancri e, "is likely covered in graphite and diamond rather than water and granite, " according to astronomer Nikku Madhusudhan from Yale University.

BBC: Oddballs: The strange worlds beyond our Solar System

Belonging to a class of worlds known as diamond planets, 55 Cancri e is thought to be rich in the element carbon, which can exist in a variety of structural forms such as graphite (the material used as pencil lead), graphene, or diamond.

BBC: Oddballs: The strange worlds beyond our Solar System