(Antofagasta, Chile) IIA Hexahedrite (iron)
This rare meteorite is a hexahedrite - hexahedrites are a class of iron meteorite with a very low nickel content and a six-sided, cubic crystal structure. When etched, no familiar eight-sided Widmanstatten pattern that is usually associated with octahedrite iron meteorites appears; instead a fine series of parallel lines called Neumann Lines are revealed.
The preparation prior to etching hexahedrites is everything - the last traces of cutting and grinding marks have to be carefully polished out to give a mirror-like finish capable of showing such finely detailed Neumann lines. Etching North Chile requires some fine-tuning of the nitric acid to alcohol ratio too, but once the optimum mix is acheived, some beautifully detailed hexahedrite slices are possible.
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