What is Trinitite?

Trinitite, also known as Atomite or Alamogordo Glass, is an unusual mineral created in the aftermath of the first nuclear bomb test, Trinity, on 16 July 1945 near Alamogordo, New Mexico. It is a green, glassy residue created when sand was fused together by the tremendous heat of the nuclear fireball. Trinitite is slightly radioactive and is highly prized among collectors, to which it was distributed in the late 1940s, after the test. In 1952, the Atomic Energy Commission bulldozed the site, burying much of the remaining trinitite, and it is illegal to remove materials from the site. Occasionally, the term trinitite is also extended to fused glass created in other atomic explosions.

The temperature at the center of a nuclear fireball is millions of degrees F, descending to thousands of degrees F as the fireball dissipates. The melting point of pure silica is about 4200 degrees F, so any sand exposed to such a temperature is likely to be transformed into trinitite. By testing the fission products left over in minute quantities in trinitite, it is possible to infer what nuclear bomb explosion it came from. After a nuclear explosion in a desert, a so-called "glass parking lot" is created beneath it, a term coined shortly after the first test explosion.

Trinitite is not dissimilar to impactite, another mineral created when a meteor explodes in an airburst, heating up the sand in a desert and causing it to fuse. Such minerals are found in substantial quantities at sites in Egypt, Libya, Saudi Arabia, southern Australia, and Tasmania, where they are also known as "desert glass." Desert glass tends to be clearer and more uniform than trinitite, as the temperature that created it was even more intense, allowing even melting. Areas where impactite can be found are known as strewn fields, and may extend over tens of kilometers.