This document provides an overview of X-ray diffraction (XRD). It begins by explaining that XRD is a non-destructive chemical analysis technique that uses X-rays and the atomic structure of crystals to identify substances. Every crystalline substance produces a unique XRD pattern like a fingerprint. The document then discusses how X-rays are generated via electron bombardment, Bragg's law of diffraction, X-ray sources, working principles of XRD, and basic components of an XRD system like the X-ray tube and detector. It also covers sample preparation techniques for clay minerals analysis using XRD.