Eluvial means washed out, i.e. a rock is modified by removing part of it through erosion processes. This process leads to the enrichment of those substances that are not washed out and at the same time to the depletion of substances that are displaced. Soil resources of this type are the residual formations of weathering that are found in situ.
A typical and economically most important mineral resource of this type is bauxite. It is a clay-like aluminium compound which occurs in large deposits, can be easily mined and can be reduced to aluminium by electrolysis. They are formed during the chemical weathering of rocks that are rich in aluminosilicates. During this process, all rock components are either dissolved or mechanically removed, leaving only the aluminium compounds behind.
Another material of this type is clay, the basic material for ceramics, or kaolin, the basic material for porcelain.