The conversion of crustal rocks to a granitic mineral assemblage by the action of metasomatic fluids (see metasomatism) without going through the magmatic stage. The essential chemical components of granite are introduced into the solid parent rock, and those elements not required are removed from the solid rock by the percolation of metasomatic fluids along grain margins and the diffusion of ions through crystals. ‘Granitization’ was proposed as a process for generating granites in order to get around the space problem associated with injecting large volumes of granitic magma into the crust; the idea is no longer much in vogue.