Since 1988, the authors have been measuring x-ray diffraction (XRD) spectra of small samples of layers in cross sections using a micro x-ray diffractometer (PSPC/MDG) system. In measuring with x-ray diffractometry, the position-sensitive proportional counter (PSPC) covers 150 degrees of x-ray diffraction continuously. The data are accumulated by the multichannel analyzer (MCA) and monitored on a cathode ray tube during the measurement period. Mounted samples can rotate around three axes. The XRD spectra are very like those from a wide-angle goniometer used in powder diffraction. Normally the spatial limits are around 30 microns in diameter, as was found experimentally in samples. This system seems applicable to art and archaeological studies. Some case studies are presented.