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Widmanstätten pattern

Widmansteatten pattern
A characteristic cross-hatched pattern that becomes visible on the surface of octahedrites (the commonest type of iron meteorites) and pallasites after polishing and etching with nital (nitric acid in solution with ethanol). It is due to an intergrowth of crystals of nickel-rich taenite and nickel-poor kamacite and is formed when the liquefied outer surface of an iron meteorite cools on entering the Earth's atmosphere. It is named after its discoverer, the Austrian mineralogist Alois von Beckh Widmanstätten (1754–1849), who observed them in 1808.

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