X-ray diffraction can be applied to a variety of geologic problems for the acquisition of mineralogic information. The most widely used method for preparing a specimen for a x-ray diffractometer is to fill a shallow depression with a powder sample to form a flat surface. The preparation should be a simple straight forward guide for users with no special skills. The preparation consists of two major steps: 1) sample preparation, reducing the raw sample to a 325 mesh powder; 2) packing the specimen holder. Consistency in technique of sample preparation aids the accuracy and reproducibility of the data.