Asteroid Impact Diamonds: Large asteroids can hit the earth at a velocity of 15 to 20 miles per second. This produces an impact that is powerful enough to vaporize rock, excavate a huge crater, and blast millions of tons of ejecta into the air. The force at the point of impact exceeds the temperature and pressure required to form diamonds. For diamonds to form, the target rock must contain significant amounts of carbon. The Popigai Crater in northern Russia is an asteroid impact that may have produced the world’s largest diamond deposit.