This method uses heavy presses to mimic the mantle's crushing conditions. A "diamond seed" is placed with graphite and a metal catalyst; as the metal melts, the carbon dissolves and deposits onto the seed to grow a larger crystal.
A lower-pressure alternative where a diamond seed is placed in a chamber filled with carbon-rich gases (like methane). When heated to 1,200–3,000°F, the gases break down, and carbon atoms "rain down" onto the seed, building it layer by layer. The Virtual Kiln: Diamond Recipes in Minecraft This method uses heavy presses to mimic the
In the physical world, nature’s "kiln" is the Earth’s mantle, approximately 90–125 miles below the surface. as the metal melts
Natural diamonds can take anywhere from a few days to 1 to 3 billion years to fully crystallize. the gases break down