One pair of rocks that can be used in this investigation is limestone and marble. Limestone is a sedimentary rock formed from the accumulation of organic and inorganic materials such as coral, shells, algae, and sand over millions of years. Marble, on the other hand, is a metamorphic rock that is formed when limestone is subjected to high pressure and temperature deep within the Earth's crust. This causes the minerals in limestone to recrystallize, resulting in a harder, denser rock with a distinctive veined or mottled appearance. So, limestone can be changed into marble through the process of metamorphism.
