To determine the percentage composition of minerals present in a rock sample using the X-ray diffraction XRD technique, follow these steps:1. Prepare the rock sample: Grind the rock sample into a fine powder to ensure that all mineral phases are well represented in the analysis.2. Perform X-ray diffraction analysis: Place the powdered rock sample in the XRD instrument and run the analysis. The XRD instrument will generate a diffractogram, which is a graph showing the intensity of X-rays diffracted by the sample as a function of the diffraction angle 2 .3. Identify the minerals: Analyze the diffractogram to identify the minerals present in the sample. Each mineral has a unique set of diffraction peaks, which can be matched to a database of known minerals to identify the specific minerals present in the sample.4. Quantify the minerals: To determine the percentage composition of each mineral, you will need to quantify the relative intensities of the diffraction peaks. This can be done using a method called Rietveld refinement, which involves fitting a calculated diffraction pattern to the observed pattern and refining the fit by adjusting the parameters of the crystal structure and the scale factors of the individual phases.5. Calculate the percentage composition: Once you have the scale factors for each mineral phase, you can calculate the percentage composition of each mineral in the sample. To do this, divide the scale factor of each mineral by the sum of all scale factors and multiply by 100.For example, if you have three minerals with scale factors A, B, and C:Percentage of mineral A = A / A + B + C * 100Percentage of mineral B = B / A + B + C * 100Percentage of mineral C = C / A + B + C * 100The sum of the percentages should equal 100%.Keep in mind that the accuracy of the XRD analysis depends on the quality of the sample preparation, the instrument calibration, and the expertise of the analyst. It is also important to note that XRD may not be able to detect very low concentrations of certain minerals or distinguish between minerals with very similar crystal structures.