And the only problem is that the universe is not old enough (as far as we have been able to determine) for a white dwarf to cool down enough to see if its interior would be a gigantic diamond. Arthur C. Clarke hypothesized about this back in early 70s in one of his essays. I no longer possess the anthology book that had that essay, but I remember reading it about the same time I was reading Tolkien's Lord of the Rings as it was being published here in the US back in the early 70s. He even wrote about the same thing happening in jovian planets like Jupiter in last Space Odyssey novel with a large diamond impacted on Europa after Jupiter blew up.
It is theorized it would take a white dwarf about 15 to 25 billion years to cool down. Currently, as far as I know, the universe is only 14 billion years old.
But it would be kewl to find one and mine it. Diamonds may become as cheap as glass, but mankind's population would be phenomenal by then also. Perhaps at least in the tens or hundreds of trillions, if not quadrillions.
rmfr