Planetary scientists in the United States believe that giant diamond chunks may be floating in the fluid hydrogen and helium atmospheres of Saturn and Jupiter, and that at certain altitudes the chunks melt and rain glittering liquid diamond onto the planets.
The creation of diamond rain starts in the upper atmosphere's lightning storms, where Prince has been known to perform (just kidding). Lightning storms turn Saturn’s methane gas into carbon soot, which then falls 18,0000 miles towards the planet’s core. Over the course of this fall, the soot is put under enormous pressure and undergoes multiple changes, which results in diamond rain. 1000 miles into the fall, the soot turns to graphite. Then at 3,500 miles, the graphite is crushed into diamonds. By the end of the fall, the extreme temperature and pressure have melted the diamonds into liquid rain.
Scientists have known for 30 years that diamonds may exist in the cold cores of Uranus and Neptune, but Jupiter and Saturn were thought to be too hot to have conditions suitable for precipitation of solid diamonds. However, diamonds floating close to Saturn and Jupiter's cores could be as large as icebergs, according to officials from California Specialty Engineering in Pasadena, California.
On Earth, diamonds form naturally from carbon buried about 100 miles underground. The carbon then gets heated to approximately 2,000 degrees Fahrenheit and crushed under pressure of around 725,000 pounds per square inch. It then needs to cool down quickly, which often happens as it's being carried to the Earth's surface by lava.