Exotic “Quasicrystal” is 4.5 billion Years Old and Came From Outer Space.

Princeton physicist Paul Steinhardt announced a surprise finding yesterday after years of studying a type of material structure once considered impossible. Quasicrytals are made up of shapes, such as pentagons, that are "forbidden" in crystallography because you can't fill up space with them in any regular pattern. In three dimensions, likewise, you can't fill up space with a regular repeating arrangement of icosahedrons.

Different types of alternating forbidden shapes, however, can fill up space as quasicrystals if the ratio of their frequencies is an irrational number – one that can't be expressed as a fraction, explained Steinhardt. That made a nice mathematical abstraction but most scientists didn't think such a thing would exist in the real world.

The first person to see a real quasicrystal was chemist Dan Shechtman, who discovered them in a piece of metal that had been alloyed in a lab. Scientists doubted him, too, but they came around and he won the 2011 Nobel Prize for his discovery.

But could such a thing be produced in nature? Steinhardt has spent the last 12 years trying to find out. He teamed up with Luca Bindi at the mineralogy museum in Florence, and after testing hundreds of samples, they finally came across a 'beautiful" quasicrystal. They announce this finding in 2009. "People told us it was impossible – that it couldn't be natural," Steinhardt said. Maybe they were right, he said, realizing that they needed to look deeper into the origin of the rock in question.

It came from a box that was labeled "Khatyrkite" from the Koryak Mountains in Russia. But that was just a label on a box. Maybe it contained some kind of factory-produced material and wasn't what they thought. It wouldn't be the first time a forgery made it into a mineral collection, he said.

"There's a long forensic story," he said in which they tracked down the gold prospector who picked up the rock from the ground in the 1970s. They also did additional analysis of the rock itself and realized that the ratio of oxygen isotopes present indicated it was a meteorite. It was not just an ordinary one but a type called a carbonaceous chondrite, which dated back to the beginning of the solar system. They published their findings in yesterday's issue of the Proceedings of the National Academy of Sciences.

"This is a story in which the impossible happened many times over," he said.