Accurate quantification of quartz and other phases by powder X-ray diffractometry

The 33 parameters that affect accuracy of quantitative analysis by X-ray powder diffractometry can be grouped as (1) Instrumental or systematic, (2) Inherent properties of the analyte, or (3) Parameters related to preparation and mounting of powders, The effect of each on diffraction intensity is summarized. An optimal value or range is given for instrumental parameters. Evaluation of inherent parameters of the analyte and optimization of those related to preparation and mounting of powders are discussed. Published methods are briefly reviewed. Their reported detection limits for crystalline silica are well below what can be reliably determined in natural and industrial products if one or more critical parameters are neglected, as the size and shape of coherent diffraction domains. An addendum illustrates practical consideration of major parameters during routine analysis for quartz.