English: a Selected-area electron diffraction (SAED) pattern of a ringwoodite grain along the [010] zone axis and (b) its schematic illustration. The grain contains poirierite in two different but equivalent orientations (domain 1: Poi1, domain 2: Poi2). Domain 2 is rotated by 90° along [010]Rwd compared with the orientation of domain 1. The open circles denote diffraction spots from the poirierite caused by dynamical diffraction by the overlying host ringwoodite. c High-resolution transmission electron micrograph showing 0.8 nm fringes corresponding to dPoi001. The image is published in an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).