Examples of a crystal previously thought to be impossible in nature may have come from space, a study shows.
Quasicrystals have an unusual structure - in between those of crystals and glasses.
Until two years ago, quasicrystals had only been created in the lab - then geologists found them in rocks from Russia's Koryak mountains.
In PNAS journal, a team says the chemistry of the Russian crystals suggests they arrived in meteorites.
Quasicrystals were first described in the 1980s by Israeli researcher Daniel Schechtman, who was awarded last year's Nobel Prize in Chemistry for the discovery.
Schechtman's ideas were initially treated with doubt or scorn by some of his peers, who thought the structures were "impossible".
The references given are:
- 2012, PNAS, "Evidence for the extra-terrestrial origin of a natural quasicrystal", Luca Bindi, John M. Eiler, Yunbin Guan, Lincoln S. Hollister, Glenn J. MacPherson, Paul J. Steinhardt and Nan Yao
2009, Science, Vol. 324, pp. 1306-1309, “Natural Quasicrystals”, Luca Bindi, Paul J. Steinhardt, Nan Yao and Peter J. Lu
Any one got any insight they'd like to share?