Quantitative analysis is used to determine the relative amount of each phase in a mixture, and is typically reported as Wt%. For this example, this mixture contains four crystalline phases; zincite, brucite, corundum and fluorite. The quantification of these phases was performed with Rietveld analysis which uses all lines in the pattern and produces an estimate of the errors on the weight percentage of each refined compound. Since Rietveld refinement uses the entire XRD pattern (all intensity), the percent of amorphous (non-crystalline) material can also be reported, so 100% of the material is accounted for.
Extensions of this refinement allow the determination of crystallite size and/or percent crystallinity, and micro-stress can also be determined.
Although quantitative analysis is usually accomplished by Rietveld refinement, more accurate results can often be obtained by internal or external calibration methods, in which standards can be prepared over the narrow range of expected percentages. For simple relative comparison between samples, the RIR (Reference Intensity Ratio) method can be used.