Diamonds behave like water while melting and freezing

A research into the melting point of diamond conducted by scientists at the Lawrence Livermore National Laboratory in California and published this week found the mineral behaves like water during melting and freezing, with its solid form floating on the liquid, and indicated that Neptune and Uranus may have icebergs of the precious gems. Both planets do not have magnetic poles which match up with their geographical poles. As much as 10% of them are carbon, and a liquid diamond ocean could deflect the angle of the magnetic field out of alignment with the planet's rotation, the scientists believe.

In laboratory conditions which simulated pressure levels on the gas planets, the researchers found that little crystals of solid diamond formed like icebergs in the liquid carbon they created. The researchers took a half-millimetre wide diamond a tenth of a carat in weight and blasted it with lasers at high pressure, similar to that which found on Uranus and Neptune. The gem was liquified at pressures 40 million-times greater than at sea-level on Earth, and from there the scientists slowly reduced the temperature and pressure.

When the pressure was reduced to "only" 11 million-times Earth sea level and temperatures dipped to 50,000 degress Celsius, solid chunks of diamond began to appear in the liquid. As the pressure continued to drop more and more chunks formed in the liquid diamond, and did not sink – just like water does.