TEM images of iron particles. (a) HRTEM image of an iron-rich particle region in the sample shocked at 41 GPa. The iron-rich particle is identified as magnetite, with a crystal axis orientation of $\left[\overline{3}\overline{3}\overline{3}\right]$. The dashed arrow indicates the location of the elemental line scan. (b) Elemental line scan across the magnetite particle, showing a sharp increase in Fe abundance, while O, Mg, and Si abundances decrease substantially, though the O abundance does not decrease to zero. (c) HRTEM image of an iron particle region in the sample shocked at 47 GPa. (d) FFT pattern of the iron particle shown in (c), confirming its identifications as γ-phase metallic iron (γ-Fe⁰), with a crystal axis orientation of $\left[0\overline{2}\overline{2}\right]$.