Natural diamonds crystallize in Earth’s mantle at high temperatures and pressures. The most popular method for making synthetic diamonds mimics those conditions by using anvil presses to achieve extreme pressures. Another approach, chemical vapor deposition (CVD), works at low pressures and is used to grow diamonds layer by layer on a substrate in a vacuum, a process more akin to the diamond growth that occurs in interstellar gas clouds.
Now Rodney Ruoff (at the Ulsan National Institute of Science and Technology and the Institute for Basic Science Center for Multidimensional Carbon Materials in South Korea) and colleagues have unveiled another route to diamond growth that works at ambient pressure. The approach, which involves methane and hydrogen gas and a catalyst of molten metals, requires less energy and less-advanced equipment than the two leading diamond synthesis methods.1
Below pressures of about 20 000 atm, graphite is the stable form of...
