Metamorphic rock can be formed from sedimentary or igneous rocks. Studying chemicals that make up metamorphic rock can reveal the original rock type.
Limestone is a sedimentary rock that can be metamorphosed, or changed, to make marble. Limestone and marble are both formed from a chemical called calcium carbonate.
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.
Their mineral grains grew together tightly during metamorphism, they're generally strong rocks. They're made of different minerals than other kinds of rocks and have a wide range of color and luster.
Metamorphic rocks aren’t always just formed by one type of base rock. Marble, for example, is made from the combination of limestone and chalk. Even though marble is strong, what makes it a unique rock is that it can actually be dissolved because of its core components. All it takes is some acidic products, such as lemon juice.