A measure of the intensity of chemical weathering. It consists of a comparison between a mineral or a chemical compound that is relatively stable with one that is readily removed by weathering. For example, the ratio of quartz to feldspar is a widely used index. Resistant heavy minerals are also used: the ratio between zircon and tourmaline (resistant) and the amphiboles and pyroxenes (less resistant) has been employed.
Subjects: Earth Sciences and Geography.