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

In 2010 a team of researchers from Washington State University found that artificial regolith containing silicon, aluminium, calcium, iron and magnesium oxide could be used by 3D printers to create solid objects.

BBC: 3D printed moon building designs revealed

This will map for the first time iron, magnesium, aluminium and silicon over the moon's entire surface.

ECONOMIST: Astronomy

Japanese researchers say the basalt in NWA 011 suggests the body from which it did originate had a core of molten iron with an outer covering of silicon and aluminium that formed a basaltic crust.

BBC: Mercury meteorite puzzle