Scientists Found a New Type of Crystal Formed by the World’s First Nuclear Explosion

4 min read

Here’s what you’ll learn when you read this story:

• The 1945 Trinity nuclear test fused desert sand and bomb-tower materials into trinitite—a glassy substance unlike anything humans had created before.
• Researchers recently discovered two rare crystal structures—a quasicrystal and a clathrate—coexisting within the same red trinitite sample.
• Mathematical modeling revealed that both structures formed independently from the same explosion, deepening our understanding of extreme crystallization events.

Just before dawn on July 16, 1945, an eerie silence fell over the desert at an Air Force base near Alamogordo, New Mexico. Anticipation hung thick in the early morning air as researchers and military personnel, including head physicist Robert Oppenheimer, waited for the culmination of a classified project that had taken two years to develop. Everything went white-hot at exactly 5:29:45 a.m. As the dust cleared, a tremendous cloud mushroomed out of the sand and into the sky.

Later recreated by special effects for the film Oppenheimer, the Trinity explosion marked a breakthrough as the first nuclear test ever. It had faced doubts and controversy—Oppenheimer himself had initially been skeptical about developing the plutonium bomb, codenamed “Gadget,” and remained nervous about its prospects until his mission was accomplished. When Gadget detonated atop a test tower almost a hundred feet in the air, it unleashed 18.6 kilotons of power that instantly vaporized its surroundings. Quartz and feldspar from the sand below were fused with asphalt, copper cables, and iron from the tower into a glassy, greenish substance that came to be known as trinitite. It was the first substance ever created by humans that was at all similar to the tektites left behind by meteorite impacts or the obsidian formed from volcanic lava.

In 2021, geologist Luca Bindi and his research team discovered that the explosion had bent physics to the extreme and synthesized a rare form of trinitite infused with enough copper to turn it red instead of its usual pale-green hue. They also found that parts of this red trinitite had the structure of a quasicrystal—a material whose atoms arrange themselves in highly organized patterns that, unlike in most crystals, never repeat perfectly. Recently, after studying the same red trinitite sample again, Bindi realized it was even stranger than he thought. Nestled alongside the quasicrystal was a second, entirely different type of crystal: a clathrate, in which atoms form cage-like structures that trap other atoms inside.

Gamma ray measurements revealed that the trinitite itself was formed near the end of the tower’s coaxial cable, about 180 to 197 feet from ground zero. Its glassy shine comes from melted quartz and feldspar merged into silicate glasses, with iron and copper inclusions that stood out in nano-CT scans. The clathrate, by contrast, is made of silicon atom cages—polyhedrons with 12 or 14 faces—that surround trapped calcium atoms. Its unique composition makes it the first clathrate known to emerge from a nuclear explosion. While these revelations were exciting, something was still bothering Bindi. Both the clathrate and the quasicrystal can form under the same extreme conditions of a nuclear blast, raising the possibility that the two structures might be related.

“As both the clathrate and the quasicrystal are made of typical elements found in either desert sand or the metallic tower, it seems evident that both were formed in the detonation,” he concludes in a study recently published in the journal PNAS. “The coexistence of these two rare phases naturally raises the question of whether a broader structural or topological relationship might exist between them.”

To find out if there was any link between the quasicrystal and clathrate, Bindi and his team first analyzed the structure of the clathrate by observing it with an electron microscope and X-ray diffraction. This showed that th substance is mostly composed of silicon and calcium, with traces of copper and iron. Analysis of the quasicrystal told them it occurred within metallic droplets with a high copper content, and that it’s also rich in silicon. The researchers then probed whether the mechanical and energetic stability of the clathrate was similar to that of the quasicrystal. While some quasicrystals can be produced in a lab, this one has not yet been successfully replicated, as it’s too valuable to risk potential damage in synchrotron experiments. So, the scientists tested it virtually against the stability of the clathrate using mathematical models.

It turned out that clathrate with low levels of copper was metastable, meaning that it could remain stable with no more than minor disturbances. Stability plummeted, however, as it reached the higher copper levels of the quasicrystal. This could only mean that two completely different crystal structures had formed from the same explosion. Bindi’s findings also offer more insight into how other phenomena—such as lightning strikes and meteorites hitting Earth—produce strange crystalline structures that are, as he said, “beyond the reach of conventional synthesis.”

Wherever Oppenheimer is, over eighty years after the detonation that changed physics, he must be beaming.