Trinitite, also known as atomsite or Alamogordo glass, is the glassy residue left on the desert floor after the plutonium-based Trinity nuclear bomb test on July 16, 1945, near Alamogordo, New Mexico. 

Since the early 50s it has been illegal to remove anything from the Trinity site. The Trinitite shown and sold on this site is from a group of Trinitite collected by 

Dr. Prey right before the site was bulldozed over.See Dr. Ralph Pray's account of removing Trinitite from the site: http://www.mine-engineer.com/mining/trinity.htm