Gabbro is an igneous rock formed from the cooling of molten magma. It is a dark-colored, coarse-grained rock that is composed primarily of the minerals plagioclase feldspar, pyroxene, and olivine. Gabbro is typically found in association with other igneous rocks such as granite and diorite.

Gabbro is formed when magma cools slowly beneath the Earth's surface. This allows the minerals in the magma to grow into large crystals. The composition of the gabbro will vary depending on the composition of the original magma. For example, gabbro that is formed from a magma that is rich in iron will be darker in color than gabbro that is formed from a magma that is poor in iron.

Gabbro is a common rock type in the Earth's crust. It is found in many parts of the world, including the United States, Canada, Europe, Asia, and Africa. Gabbro is used for a variety of purposes, including construction, road building, and jewelry.