Dolomite is not an igneous rock. To understand why, let`s first clarify what an igneous rock is. Igneous rocks are formed from the solidification of molten rock, known as magma or lava. They can be classified into two main types: intrusive and extrusive.

Intrusive igneous rocks, like gabbro and granite, form beneath the Earth`s surface when magma cools and solidifies slowly. Gabbro is a coarse-grained rock composed mainly of minerals like pyroxene and plagioclase feldspar. Granite, on the other hand, is a coarse-grained rock composed of minerals such as quartz, feldspar, and mica.

Extrusive igneous rocks, like basalt, form on the Earth`s surface when lava cools and solidifies quickly. Basalt is a fine-grained rock composed primarily of minerals such as pyroxene and plagioclase feldspar.

Dolomite, however, is not formed through the solidification of magma or lava. It is a sedimentary rock, which means it is formed from the accumulation and compaction of sediments, such as limestone, over time. Dolomite is primarily composed of the mineral dolomite, which is