Second Mysterious Quasicrystal Found In 4.5-billion-year-old Meteorite
A team from Princeton University and the University of Florence in Italy has discovered a quasicrystal—so named because of its mystical arrangement of atoms—in a 4.5-billion-year-old meteorite from a remote region of northeastern Russia, bringing to two the number of natural quasicrystals ever discovered. Prior to the team finding the first natural quasicrystal in 2009, researchers thought that the structures were too fragile and energetically unstable to be formed by natural processes.
"The finding of a second quasicrystal confirms that these materials can form in nature and are stable over cosmic time scales," said Paul Steinhardt, Princeton's Albert Einstein Professor of Science and a professor of physics, who led the study with Luca Bindi of the University of Florence. The team published the finding in the March 13 issue of the journal Scientific Reports.
The discovery raises the possibility that other types of quasicrystals can be formed in nature, according to Steinhardt. Quasicrystals are very hard, have low friction, and don't conduct heat very well—making them good candidates for applications such as protective coatings on items ranging from airplanes to non-stick cookware.
The newly discovered quasicrystal, which is yet to be named, has a structure that resembles flat 10-sided disks stacked in a column. This type of structure is impossible in ordinary crystals, in which atoms are packed closely together in a repeated and orderly fashion. The difference between crystals and quasicrystals can be visualized by imagining a tiled floor: Tiles that are 6-sided hexagons can fit neatly against each other to cover the entire floor. But 5-sided pentagons or 10-sided decagons laid next to each will result in gaps between tiles. "The structure is saying 'I am not a crystal, but on the other hand, I am not random either,'" Steinhardt said.