Fig. 1. Scanning electron micrographs (SEMs) of mineral powders. (A) quartz, (B) calcite, (C) 
-alumina, (D) kaolinite. The scalebar in the SEM image of the quartz powder is 20 µm, whereas the scalebar in the other images is 2 µm.
Fig. 1. Scanning electron micrographs (SEMs) of mineral powders. (A) quartz, (B) calcite, (C) -alumina, (D) kaolinite. The scalebar in the SEM image of the quartz powder is 20 µm, whereas the scalebar in the other images is 2 µm.