Knowledge of the chemical properties of materials is important in several geomorphological contexts, water quality (see Sec. 4.3) being an obvious example, but it is often necessary to know the chemistry of weathering reactions or of sediments and soils. In this section there are two main areas: the analysis of solutions for specific ions and the determination of mineralogy. The latter is particularly important in giving a comprehensive explanation of soil behaviour, whether from a soil mechanical or pedological approach. Both areas of analysis require expensive equipment for detailed examination or where many samples are to be analysed. Although the instruments and methods are outlined here, the procedure for a particular analysis may vary widely and it is vital to be sure of the appropriate method. Suitable reading that covers these points is suggested in each section.