www.britannica.com/science/metamorphic-rockMetamorphic rock, any rock that results from the alteration of preexisting rocks in response to changing conditions, such as variations in temperature, pressure, and mechanical stress, and the addition or subtraction of chemical components. The preexisting rocks may be igneous, sedimentary, or other metamorphic rocks.
en.wikipedia.org/wiki/Metamorphic_rockMetamorphic rocks arise from the transformation of existing rock types, in a process called metamorphism, which means "change in form". The original rock is subjected to heat (temperatures greater than 150 to 200 °C) and pressure (100 megapascals (1,000 bar) or more), causing profound physical or chemical change.The protolith may be a sedimentary, igneous, or existing metamorphic rock.
geology.com/rocks/metamorphic-rocks.shtmlMetamorphic rocks have been modified by heat, pressure, and chemical processes, usually while buried deep below Earth's surface. Exposure to these extreme conditions has altered the mineralogy, texture, and chemical composition of the rocks. Minerals: Information about ore minerals, gem materials ...
www.usgs.gov/faqs/what-are-metamorphic-rocks-0Metamorphic rocks started out as some other type of rock, but have been substantially changed from their original igneous, sedimentary, or earlier metamorphic form. Metamorphic rocks form when rocks are subjected to high heat, high pressure, hot mineral-rich fluids or, more commonly, some combination of these factors.
www.thoughtco.com/about-metamorphic-rocks-1438952Metamorphic rocks are the third great class of rocks. They occur when sedimentary and igneous rocks become changed, or metamorphosed, by conditions underground. The four main agents that metamorphose rocks are heat, pressure, fluids, and strain. These agents can act and interact in an almost infinite variety of ways.
www.onegeology.org/eXtra/kids/metamorphic.htmlOther common metamorphic rocks are called marble, gneiss, schist. More information. A metamorphic rock is a result of a transformation of a pre-existing rock. The original rock is subjected to very high heat and pressure, which cause obvious physical and/or chemical changes. Examples of these rock types include marble, slate, gneiss, schist.
www.thoughtco.com/metamorphic-rock-types-4122981Metamorphic rocks are an important topic in geology.These are the rocks that form by the effects of heat, pressure, and shear upon igneous and sedimentary rocks.
www.sciencekids.co.nz/sciencefacts/earth/metamorphicrocks.htmlExamples of metamorphic rocks include anthracite, quartzite, marble, slate, granulite, gneiss and schist. Anthracite is a type of coal with a high carbon count, few impurities and with a high luster (meaning it looks shiny). Marble is a metamorphic rock that is formed from the sedimentary rock limestone.
www.bbc.co.uk/bitesize/guides/zgb9kqt/revision/4Metamorphic rocks are formed from other rocks that are changed because of heat or pressure. They are not made from molten rock – rocks that do melt form igneous rocks instead. Earth movements ...
www.nationalgeographic.org/encyclopedia/metamorphic-rocksAlthough metamorphic rocks typically form deep in the planet’s crust, they are often exposed on the surface of the Earth. This happens due to geologic uplift and the erosion of the rock and soil above them. At the surface, metamorphic rocks will be exposed to weathering processes and may break down into sediment.