New research on a rock collected by the Apollo 17 astronauts has revealed evidence for a mineral phase that can only form above 2300 °C. Such temperatures are uniquely achieved in melt sheets following a meteorite impact, allowing the researchers to link the 4.33-billion-year-old crystal to an ancient collision on the Moon. The study opens the door for many of the more complex rocks on the Moon to have formed in these destructive environments.