Dimensional changes induced by dehydroxylation are known to cause buckling of individual kaolinite layers . Whilst these changes are substantial at the scale of the crystallographic unit cell, the visible changes in particle stacking in TEM images are relatively modest (Figure ). Whilst there does seem to be some evidence of subtle disruption in stacking, there was no dramatic change in particle morphology. These observations align with previous studies of kaolinite calcination via TEM and optical microscopy , which show that dehydroxylation induces a minor reduction in layer thickness and stacking faults, but does not cause extensive delamination. Al K-edge EEL spectra of the low-Fe clays have the expected shape or profile of kaolinite ); spectra were normalised to the main K-edge peak of kaolinite (at 1575 eV at the as-acquired energy calibration) in order to more clearly observe the differences in Al K-edge profile between samples (Figure ). In the previous sections, the term "mid-range" resonance was used to describe the central resonance in the 27 Al MAS-NMR spectra, given uncertainty over its assignment to either 5-fold Al or 4-fold Al in a highly disordered environment. For the EEL spectra, 4-fold and 5-fold Al will be referred to specifically, as the previously mentioned debate does not readily translate to EEL spectra. The calcined low-Fe clay's spectrum showed a clear increase in relative intensity in the onset region of the edge profile (~1566 eV onwards) in comparison to the as-received low-Fe clay. This earlier edge onset coupled with an increase in intensity in this region and a drop in intensity of the first major feature relative to the high energy tail of the edge is due to a shift to Al in tetrahedral rather than octahedral co-ordination . The change in edge profile can be attributed to a decrease in size of the Al co-ordination shell and loss of inversion symmetry leading to a wider variety of possible final electron states accessible for Al in tetrahedral rather than octahedral co-ordination. Such a 'fingerprint' for an increase in intensity at the Al K-edge onset upon the transition from 6 to 4-fold Al co-ordination has also been demonstrated by Al K-edge X-ray Absorption Spectroscopy (XAS) for a range of aluminosilicate minerals including kaolinite . The change of Al co-ordination after calcination was consistent with the observations from the 27 Al MAS NMR spectra (Figure ) however, whilst the measured EELS Al K-edges can easily distinguish between 6-fold and 4/5-fold Al co-ordination, they do not readily distinguish 4-fold from 5-fold co-ordination (this parallels who were unable to uniquely identify 5-fold Al co-ordination in aluminosilicate glasses using STEM-EELS at the Al L-edge).