Valentine's Day Gift Ideas: A 10 Decillion Carat Diamond

Lucy in the sky:

Twinkling in the sky is a diamond star of 10 billion trillion trillion carats, astronomers have discovered. 

The cosmic diamond is a chunk of crystallised carbon, 4,000 km across, some 50 light-years from the Earth in the constellation Centaurus.

It's the compressed heart of an old star that was once bright like our Sun but has since faded and shrunk.

Astronomers have decided to call the star "Lucy" after the Beatles song, Lucy in the Sky with Diamonds.

The Great Star of Africa, enjeweled in the British Royal Sceptre, is worth an estimated $400 million and, at 530 carats, is 0.0000000000000000000000000000053% the size.

It's hard to suss out Lucy's actual value, since grading it would require "a jeweller's loupe the size of the Sun."

Mining it could also present challenges.