Quasicrystal Found In Russian Meteorite Is Only The Third To Be Discovered In Nature

Until just a few years back, the existence of natural quasicrystals - unique materials that are neither crystalline nor amorphous - was considered an impossibility. Over the past five years, however, scientists have discovered two of these in nature, both from a meteorite discovered in the Khatyrka region of northeast Russia in 2011.

Another quasicrystal has now been discovered by scientists analyzing this meteorite. However, unlike the first two - which were created in a lab before they were discovered in nature - this one has no artificial analogues.

"It's the first example of a natural quasicrystal whose chemistry has never been synthesized previously," Paul Steinhardt, a physicist at Princeton University, who was part of the team that made the discovery, told ResearchGate. "Nature made it before humans did."

Before the existence of quasicrystals was theorized in the 1980s, we knew of only two kinds of solids - crystalline and amorphous. Crystals consist of atoms arranged in an ordered lattice that repeats itself, while amorphous solids are completely chaotic.

"Quasiperiodic crystals are still crystals - they have nothing to do with amorphous materials," Israeli chemist Daniel Shechtman, who won the Nobel Prize in 2011 for the discovery of quasicrystals in a synthetic material, told Motherboard. "Amorphous materials are non-ordered (like glass), quasicrystals are crystals, but the atomic relation within them is different than periodic crystals. It is perfectly ordered, but not periodic."

As a result of this unique property, quasicrystals contain more complex forms of symmetry. While crystals can exhibit only two, three, four, or six-fold rotational symmetry, quasicrystals can exhibit seemingly "impossible" five-fold symmetry in two dimensions and icosahedral symmetry in three dimensions.

The newly-discovered quasicrystal also exhibits a five-fold rotational symmetry associated with an icosahedron - a geometric structure with 20 faces.

"The Khatyrka meteorite definitely contains parts that date back more than 4.5 billion years to the beginning of the solar system. We think one of the three quasicrystals we have found formed at the same time," Steinhardt told ResearchGate. "But the new one being reported here is probably made as a result of a high velocity collision that our meteorite encountered 300 million years ago while it was still in space. We estimate it landed on the Earth less than 20,000 years ago."

Although the discovery does provide invaluable insights into the nature of these bizarre forms of matter, bringing us closer to synthesizing more of them in labs, the practical applications of quasicrystals are still not entirely clear.

"None of the ones discovered so far really have any use other than 'wow, this is cool,'" Paul Asimow, a professor of geology and geochemistry at the California Institute of Technology, told New Scientist. "But it's not out of the question that someone will find a really good use for quasicrystals one of these days."