Crystal chemistry is a branch of chemistry that focuses on understanding the structure, properties, and behavior of crystals. Crystals are solid materials composed of repeating patterns of atoms or molecules, and crystal chemistry aims to explain how these repeating patterns influence the physical and chemical characteristics of the crystals. Crystal chemists study the arrangement of atoms within crystals, the bonding interactions between atoms, and how these factors dictate a crystal's properties such as hardness, color, and conductivity. By understanding the principles of crystal chemistry, researchers can develop new materials with specific properties for various applications, including in electronics, medicine, and materials science.