Beyond slag and shale temper, additional non-plastic inclusions comprise calcareous sand, igneous rock fragments, quartz (sometimes coarse-grained), feldspars and, rarely, sandstone and siltstone. The slag inclusions angular and appear in sizes of 0.08–2.9 mm. Their abundance varies, from as much as 13% of the thin section down to a single, small particle constituting but a fraction of a percent within the clay mass.