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. The glass is primarily made of arkosic sand composed of quartz grains and feldspar that was melted by the atomic blast. It was first academically described in American Mineralogist in 1948.