They say diamonds are a girl’s best friend. But what may be even more rare, if not considered more precious yet, are black diamonds.

No one has ever uncovered a black diamond in a mining field. Black diamonds have only been found in Brazil and the Central African Republic and if two scientists from Florida International University are correct, they may be even more rare than we thought.

In a paper published online in the Atrophysical Journal Letters, Jozsef Garai and Stephen Haggerty, along with Case Western Reserve University researchers Sandeep Rekhi and Mark Chance, claim that black diamonds originated in outer space.

Black diamonds, called carbonado, are not formed in the way conventional diamonds are and their high hydrogen composition leads scientists to place their origin in interstellar space.

According to Haggerty, carbonado diamonds are formed in stellar supernovae explosions and were once the size of asteroids when they first landed on earth.