Lonsdaleite

Hexagonal polymorph of carbon (C) that forms from meteoric graphite during impact. The immense heat and stress of the impact transforms the graphite into diamond, but retains graphite’s hexagonal crystal lattice (below). Lonsdaleite was first identified from the Canyon Diablo meteorite at Barringer Crater (also known as Meteor Crater) in Arizona in 1967. Named after first woman president of the International Union of Crystallography, Dame Kathleen Lonsdale (28 January 1903 – 1 April 1971).