Certain crystallite populations in microwave plasma CVD-grown diamond films contain large octahedral grains oriented with  normal to the film and topped by (001) facets several tens of micrometres in edge length. These facets show characteristic growth step patterns and related characteristic cathodoluminescence patterns. Conflict between the interpretation of step patterns and the facet surface profiles determined interferometrically required a quadrantal division of (001) facets by low-angle boundaries for its explanation. Misorientation determination by electron channelling and electron backscatter diffraction techniques confirmed this model; and partially polarized cathodoluminescence attributed to dislocations associated with the low-angle boundaries was observed. Occurrences of this misorientation texture in (001)-faceted CVD-grown crystallites, without restriction to particular growth techniques, are to be expected.