While some byproducts recall an idyllic piece of Americana, others remind us that the past is not always so bright and cheerful. Trinitite, created unintentionally during the development of the first atomic bomb, is arguably one of these byproducts.
A Trinitite pendant. Image via Galactic Stone
Whereas Fordite kept growing back for decades, all Trinitite comes from a single event — the Trinity nuclear bomb test near Alamogordo, New Mexico on July 16, 1945. Also called ‘atomsite’ and ‘Alamogordo glass’, ‘Trinitite’ is the name that stuck.
There wasn’t much interest in the man-made mineral initially, but people began to take notice (and souvenirs) after the war ended. And yes, they made jewelry out of it.
Although there is still Trinitite at the site today, most of it was bulldozed over by the US Atomic Energy Commission in 1953, who weren’t too keen on the public sniffing around.
There was also a law passed that made it illegal to collect samples from the area, although it is still legal to trade Trinitite that was already on the market. As you might expect, Trinitite is rare, but it’s still out there today, and can even be bought from reputable sources such as United Nuclear.
The Formation Event
On that fateful day, the plutonium bomb nicknamed “Gadget” was strapped to a 100-foot tower atop a bed of sandy soil. The detonation left a crater half a mile across and eight feet deep of radioactive glass.
The Trinity blast. Public domain via Wikimedia Commons
While at first it was assumed that the sand that became Trinitite melted at ground level, it has somewhat recently been theorized that the sand was sucked up into the fireball, liquefied, then rained down to form a sheet of glass of varying thickness, composition, and topology.
It’s estimated that the glass was formed by 4,300 gigajoules of heat energy, and the sand was exposed to a minimum temperature of 1,470 °C (2,680 °F) and super-heated for two or three seconds before solidifying into Trinitite.
In September 1945, Time magazine reported that the site looked like “a lake of green jade”, with the glass taking strange shapes, like those of “lopsided marbles… broken, thin-walled bubbles, green, worm-like forms.” The marbles suggest that some material solidified in the air on the way down.
Not all Trinitite is bottle-green, although most of it is. Some red Trinitite was discovered in one part of the site, and there are rare black pieces that are thought to contain iron. It’s been theorized that green Trinitite gets its color from the material in the support tower, while red specimens include copper from the electrical wiring.
A Unique Composition
A stack of Trinitite. Image via the University of New Mexico
Geologically speaking, Trinitite is made up of a chaotic mixture that varies both its structure and composition. A typical sample has been described as 1 to 3 cm thick, with a smooth side and a rough side from landing in a molten state on the desert floor. The upper surface is usually sprinkled with dust, while the bottom is thicker and grades into the soil it came from. Far from completely solid, it is estimated that around 30% of Trinitite is void space, and usually has cracks.
Optically, there are two forms of Trinitite with different refraction indices — the lower-index type is mostly silicon dioxide, while the higher-index glass has mixed components. Although deemed safe to handle, Trinitite is measurably radioactive. The level of radioactivity fluctuates based on the size of the specimen and its distance from ground zero.
The First of Many Atomsites, Unfortunately
As you might imagine, glassy residues remain wherever nuclear weapons detonate at or near ground level. Some scientists prefer to call all other glasses ‘atomsite’, although plenty of site- and creator-specific names have been given to the byproducts of other detonations. It was discovered in 2016 that, following the bombing of Hiroshima, between 0.6% and 2.5% of the sand on local beaches consisted of fused glass spheres that had formed. It has been called Hiroshimaite.
Trinitite is known as a melt glass or glass melt, which basically means that the silica from the ground bonded with surrounding minerals originating from both the tower and the bomb itself. While this formation process is a man-made one, there are similar natural processes that produce glassy byproducts. Stay tuned!