Temperatures must reach at least 2,200 degrees Fahrenheit with a pressure of roughly 727,000 pounds per square inch .
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 Temperatures must reach at least 2,200 degrees Fahrenheit
For those who can't wait a billion years, modern technology uses "lab kilns" through two primary methods: Temperatures must reach at least 2