Swathing kamacite
Swathing kamacite is a band of kamacite that surrounds inclusions such as schreibersite or troilite in iron meteorites.
Swathing kamacite is a rim of low-nickel kamacite metal that encloses an inclusion, such as a crystal of schreibersite or a troilite nodule, in an iron meteorite. On an etched slice it appears as a smooth band surrounding the inclusion, interrupting the Widmanstätten pattern around it.
It forms because the inclusion acted as a convenient starting point for kamacite growth as the metal cooled. Schreibersite in particular takes up nickel, leaving the surrounding metal depleted and encouraging kamacite to form there. The swathing band can grow to several millimetres wide.
Swathing kamacite is a good example of how small details on an etched surface reveal the cooling history of an asteroid core. Its width, along with the kamacite band widths elsewhere, helps metallurgists understand how phosphorus and nickel moved through the metal over millions of years of slow cooling.
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