metamorphic

adjective

1. pertaining to or characterized by change of form, or metamorphosis.
2. Geology. pertaining to or exhibiting structural change or metamorphism.

adjective

1. relating to or resulting from metamorphosis or metamorphism
2. (of rocks) altered considerably from their original structure and mineralogy by pressure and heatCompare igneous, sedimentary

adj.1833 (Lyell) in the geological sense, in reference to rock whose form has been changed by heat or pressure, from metamorphosis + -ic. Earlier (1816) in non-technical sense “characterized by change.”

1. Zoology Relating to metamorphosis.
2. Geology Relating to rocks that have undergone metamorphism. Metamorphic rocks are formed when igneous, sedimentary, or other metamorphic rocks undergo a physical change due to extreme heat and pressure. These changes often produce folded layers or banding in the rocks, and they can also cause pockets of precious minerals to form. The folds and banding can be produced by incomplete segregation of minerals during recrystallization, or they can be inherited from preexisting beds in sedimentary rocks or preexisting layers in igneous rocks. The precious minerals can form as the result of recrystallization when the rocks undergoing metamorphism are subjected to changes in pressure and temperature.