metamorphic and sedimentary rocks. Figure 1.1: Approximate mineral compositions of the more common types of igneous rocks, e.g. granite approximately 40% orthoclase, 33% quartz, 13% plagioclase, 9% ...

This used to be sand and other sediment - that's why it is called sandstone - which is a type of sedimentary rock. Sedimentary rocks are formed when pieces of rock are eroded, or worn away ...