The document discusses various sample preparation and presentation techniques for X-ray diffraction (XRD) analysis. An ideal powder sample consists of many randomly oriented crystallites between 40-1 micrometers in size. Proper grinding and sieving can achieve the desired particle size. Back loading and using a zero-background holder are common techniques to present samples as flat plates for analysis. Special cases may require protecting samples in reaction chambers or capillaries to avoid contamination or preferred orientation.