The largest diamond ever found is not on Earth, but faraway across the galaxy. It's the burned out corpse of a star named BPM 37093 only about 50 lightyears away from Earth in the region of the sky we refer to as the constellation Centaurus. The white dwarf star is a chunk of crystallized carbon that weighs 5 million trillion trillion pounds. That would equal a diamond of 10 billion trillion trillion carats.