Compositions and microstructures of the primary ceramic materials in the paleolithic age through XRD, SEM, and TEM analyses

The mineral compositions and microstructures of Paleolithic materials were first investigated by X-ray diffraction analysis, scanning electron microscopy, and transmission electron microscopy in order to understand the primary ceramic material in human history. Shale and chalcedony artifacts excavated from upper Paleolithic sites were analyzed. As a result, from among various candidates with nonuniform mineral compositions, only limited materials containing polycrystals with approximately more than 95%α-quartz content were selected as tool materials. Moreover, every Paleolithic material invariably exhibited densely packed and homogeneous micrograins approximately 0.1-0.5 μm in size and an equigranular structure with few porosities at the grain boundaries.