There are no diamonds in Uranus*

I'm not sure who first suggested the possibility that the atmospheric pressure on gas giant planets might create diamonds, but it has been a staple of science writers and editors for years. And why shouldn't it be? The images are irresistible. Picture millions of tiny diamonds falling from the sky in a gentle rain or a single moon sized diamond forming a planetary core beneath thousands of miles of colored clouds. Push those images out of your mind. The latest word out of Amsterdam--and really, who knows more about diamonds--is that it probably isn't true.

Physicists at the Universtiet van Amsterdam and the FOM Institute for Atomic and Molecular Physics in the Netherlands performed a numerical analysis showing that at the temperatures and pressures in gas giant planets like Uranus, arrangements of carbon atoms would be much more suitable for creating tiny bits of graphite rather than diamond.

For some reason, a gentle rain of pencil lead doesn't have the same appeal.

On the other hand, we don't need to completely give up on our diamond dreams yet.

In white dwarfs, on the other hand, the simulation shows that the conditions would cause the carbon atoms to line up in configurations that are much more amenable for diamond crystallization. The conclusion is consistent with the 2004 discovery of a cooling white dwarf star that appears to have a solid diamond core 4000 kilometers across.

We just need to go farther to look for them.

* Insert bawdy joke here.