In pictures: Diamond-shaped asteroid

"We observed a new jewel in the Solar System," said Uwe Keller, head of cameras on the European Space Agency's (Esa) Rosetta probe, likening asteroid Steins to a "diamond in the sky".

Rosetta flew past the rock at a distance of about 800km, giving scientists a rare opportunity to take these images. The probe's ultimate goal is to catch and orbit a comet near Jupiter in 2014.

The European Space Agency said the images showed several small craters on the asteroid and two huge ones, one of which is 2km in diameter, indicating the asteroid must be very old.

The asteroid is about 360m km (224m miles) from Earth, but measures just 5km across. "Steins might be small, but we're making big science here," said an Esa spokesman.

The probe is passing through the asteroid belt between Mars and Jupiter, comprising the leftovers that were not incorporated into planets when the Solar System formed 4.6 billion years ago.

It singled asteroid Steins out using one of its navigational cameras from a distance of about 24m km on 4 August 2008.