 The key discovery was the presence in the crater of the minerals coesite and stishovite, rare forms of silica found only where quartz-bearing rocks have been severely shocked by an instantaneous overpressure.It cannot be created by volcanic action; the only known mechanisms of creating it is naturally through an impact event, or artificially through a nuclear explosion.In 1960, Edward C. T. Chao and Shoemaker identified coesite at Meteor Crater, proving the crater was formed from an impact generating extremely high temperatures and pressures.