what precious material rains on neptune and uranus

According to multiple sources, including, , , , and, it rains diamonds on Neptune and Uranus. The diamonds form in the hydrocarbon-rich oceans of slush that swath the gas giants solid cores, where hydrogen and carbon atoms are smushed together under immense pressure, forming the crystals. The diamonds are thought to sink slowly further into the interior of the planets, where they could assemble as a thick layer around the solid planetary core over thousands of years. The diamond rain was first proposed before the Voyager 2 mission, and scientists have since tried to recreate the conditions inside Neptune and Uranus in a lab to better understand how the molecular magic happens.