Icosahedrite
The first natural quasicrystal — an aluminium-copper-iron alloy from a meteorite with forbidden five-fold symmetry, approved in 2010.
Intro adapted from Wikipedia (CC BY-SA).
Icosahedrite is an IMA-recognized mineral species in the native element class, with the chemical formula Al₆₃Cu₂₄Fe₁₃.
Key properties: Gray streak; Metallic luster.
IMA symbol Ihd, IMA status: approved, named in 2010.
Likely formed by impact-induced shock in the Khatyrka meteorite, a CV3 carbonaceous chondrite.
It is found associated with Spinel, diopside, forsterite, nepheline, sodalite, corundum, stishovite, khatyrkite, cupalite, an unnamed AlCuFe compound.
The name refers to the icosahedral symmetry of its atomic structure, as observed in its diffraction pattern.
Index entry. This entry combines official IMA/RRUFF species data with published physical-property data and a Wikipedia introduction — a full written entry hasn’t been published yet.
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