Quasicrystals. Materials with ordered but non-repeating atomic patterns. Were first found in a meteorite stored here after a Siberian expedition.
Paul J. Steinhardt et al., CC BY 4.0
A crack in the laws of nature
For over a century, a core principle of crystallography was the "crystallographic restriction theorem." It states that the atomic patterns within a crystal can only have two, three, four, or six-fold rotational symmetry. Five-fold symmetry was considered impossible because it could not form a repeating, periodic lattice that fills all of space. This fundamental rule was broken in 1982 when materials scientist Dan Shechtman, while examining a rapidly cooled alloy of aluminum and manganese, observed a diffraction pattern with ten-fold symmetry. In his lab notebook, he famously wrote "10 Fold?" This pattern showed an underlying atomic structure with five-fold symmetry, a direct violation of the established laws.
Shechtman's discovery of what are now called "quasicrystals" was met with extreme skepticism. Quasicrystals are materials whose atoms are arranged in ordered, predictable patterns, much like true crystals, but these patterns never repeat. They exhibit long-range order without the translational symmetry of conventional crystals. The discovery was controversial that Shechtman was asked to leave his research group. Despite the resistance, the evidence was undeniable, and Shechtman was awarded the Nobel Prize in Chemistry in 2011 for his work.
A cosmic origin story
For decades, quasicrystals were purely a laboratory creation. The question remained whether they could form naturally. Physicist Paul Steinhardt of Princeton University, who had independently theorized about quasicrystals in the 1980s, began a systematic search for a natural specimen. The search led him to a small rock sample in a Florence museum, which was found to contain a microscopic grain of a quasicrystal with the composition Al63Cu24Fe13. This first natural quasicrystal was officially named icosahedrite.
The sample was traced back to the Khatyrka meteorite, a CV3 carbonaceous chondrite that formed around 4.5 billion years ago. To confirm the origin and find more material, a rugged expedition was launched to the Koryak Mountains of Chukotka in far eastern Russia. In 2011, the team successfully recovered more fragments of the meteorite. Analysis of these samples, some of which were processed in Voronezh, confirmed the extraterrestrial origin of the quasicrystals.
The evidence shows the quasicrystals formed under extreme conditions in the early solar system. A high-velocity collision between asteroids, generating pressures over 5 gigapascals and temperatures above 1,200°C, followed by rapid cooling in the vacuum of space, created the unique conditions needed for this "impossible" material to form. To date, the Khatyrka meteorite is the only known natural source of quasicrystals on Earth.
💡Fun Facts
The atomic structure of quasicrystals is analogous to Penrose tilings, a type of pattern that uses two or more tile shapes to cover a plane without ever repeating.
Dan Shechtman, the discoverer of quasicrystals, was famously told by double Nobel laureate Linus Pauling, "There is no such thing as quasicrystals, only quasi-scientists."
A second, even rarer type of natural quasicrystal with ten-fold (decagonal) symmetry and the formula Al71Ni24Fe5 was later discovered in another grain from the same Khatyrka meteorite.
Synthetic quasicrystals are now used in applications ranging from non-stick cookware to durable surgical steel because they are hard, have low friction, and are poor conductors of heat.
