【鉱物学】宇宙から飛来した隕石から見つかった新しい準結晶

The discovery of a new quasicrystal is detailed in an article published online in Scientific Reports this week. The mineral was identified in a fragment from a meteor which landed in Khatyrka in eastern Russia, and is the first quasicrystal to be discovered in nature prior to being synthesized in the lab.

Quasicrystals are crystal-like structures, in which the atoms are arranged in orderly patterns that never exactly repeat and have an infinite number of possible symmetries. The new crystal was found in a fragment from the Khatyrka meteorite, which was recovered during an expedition to the Koryak Mountains in far eastern Russia in 2011.

Paul Steinhardt and colleagues identified the new composition on a grain from the meteorite that also contains the naturally occurring mineral icosahedrite. The authors note that like icosahedrite, the new quasicrystal has icosahedral symmetry (i.e. it has 60 points of rotational symmetry). The authors suggest that the newly identified quasicrystal may have crystallized under high pressure following a period of melting induced by a shock, such as an impact with another object in outer space. The authors note that this is only the third example of a natural quasicrystal to be found anywhere in the world, all of which come from the Khatyrka meteorite.