Which one of the following is not an igneous rock?
Three types of rocks are: igneous, sedimentary, and metamorphic. Igneous rock (also called magmatic rock) is formed through the cooling and solidification of magma or lava.
Dolomite is a sedimentary rock composed primarily of the mineral dolomite, CaMg(CO3)2. Sedimentary rocks are formed by the deposition and subsequent cementation of that material at the Earth's surface and within bodies of water.
Metamorphic rocks are formed by subjecting any rock type (sedimentary rock, igneous rock or another older metamorphic rock) to different temperature and pressure conditions than those in which the original rock was formed.
The correct option is C.