Gabbro is an igneous rock which has crystallized deep in the Earth. Since the rock cooled and hardened (and crystallized) deep below the Earth’s surface, it will be coarse grained. High pressure is usually found deep below the surface of the earth. Here, molten material cools very slowly. The igneous rocks produced have large crystals.

 . Gabbro has the same mineral composition as basalt (olivine and pyroxene with smaller amounts of feldspar and mica). Whether basalt or gabbro forms depends upon the cooling rate of the magma, not the composition of the magma. Gabbro is coarse grained while basalt is fine grained.

. Gabbro is sometimes called “black granite” for it too is coarse- grained, but a large proportion of iron bearing minerals make gabbro heavier and dark colored. Gabbro can also be grey or light green.

• Gabbro is widely used as crushed stone for concrete aggregate, road base material, and railroad ballast. Smaller quantities are cut and polished for dimension stone and called black granite.

Uses of Gabbro

. The most important use nowadays is its utilization in the formation of artificial islands, commercial/cargo/container terminals, birthing /un birthing facilities, off sure jackets and oil/gas/chemical terminals as most reliable known water resistant base. It works like a natural glass container to hold water without any countable seepage

. The other common use of gabbro is as a crushed stone or aggregate. Crushed gabbro is used as a base material in construction projects, as a crushed stone for road construction, as railroad ballast, and anywhere that a durable crushed stone is needed as fill.