clean up & uniformity
'''Metamorphic rocks''' are created when existing [[
Igneous_rock|igneous]] or [[ Sedimentary_rock|sedimentary]] [[rock |rocks]] are squashed, stretched and/or cooked and change their appearance and [[mineral]] composition.
Some metamorphic rocks have [[course-grained]] minerals that occur in wavy bands. Others are very [[fine-grained]]. Most are hard and difficult to break.
*Kavanaugh, James. ''Pocket Naturalist - Geology - An Introduction to familiar Rocks, Minerals, Gemstones & Fossils'', Waterford Press: Arizona (2000)