Quasicrystals in the Wild: Meteorites, Lightning, and an Atomic Bomb

Quasicrystals — ordered but non-repeating atomic arrangements, the 3D analog of Penrose tiles — almost never form on their own. Mathematician John Carlos Baez catalogs the entire known set of natural and quasi-natural specimens, and the list is remarkably short. Three were recovered from a single meteorite that fell in Khatyrka, Russia, which is also the only known meteorite containing metallic aluminum and appears to be the product of an ultra-high-velocity asteroid collision.

The Khatyrka trio are icosahedrite (Al-Cu-Fe with full icosahedral symmetry), decagonite (Al-Ni-Fe with tenfold symmetry stacked periodically), and i-Phase II (a copper-rich icosahedral variant that was found in nature before ever being synthesized). Their structures can be derived mathematically by slicing and projecting higher-dimensional lattices — the D6 lattice for the icosahedral phases and the A4 lattice for decagonite. Two more borderline cases round out the inventory: a manganese-silicon dodecagonal quasicrystal found in a fulgurite near a downed power line in Nebraska, and a silicon-dominated icosahedral phase pulled from the fused desert glass of the Trinity nuclear test site.

The takeaway is that quasicrystal formation in nature requires extreme, transient conditions — hypervelocity impacts, lightning strikes, or nuclear detonations — which is why every other known specimen has been grown in a lab. The Nebraska find also blurs the definition of “natural,” since it is unclear whether the triggering arc came from lightning or the fallen power cable itself.