Sedimentary rocks are formed by small rock pieces which are transported by rivers and laid down in layers. Chalk is a sedimentary rock. Metamorphic rocks are formed when another rock is under heat ...

Ed. Calcium carbonate (CaCO 3) is a natural product found in many settings, including the minerals aragonite 1 and calcite 2; the sedimentary rocks limestone 3 and chalk 4; and animal structures such ...