Diabase facts for kids

Diabase

Diabase is a type of igneous rock that often looks dark blue or green. It's full of minerals like magnesium and iron. This rock forms when hot, melted rock (called magma) cools down and hardens underground, usually in cracks or layers near volcanoes. You might also hear it called dolerite or microgabbro.

What is Diabase?

Diabase is an igneous rock, which means it forms from cooled magma or lava. It's a bit like granite or basalt, but it forms in a special way. Diabase usually has small to medium-sized mineral grains that you can often see without a magnifying glass. These grains are usually plagioclase feldspar and pyroxene, which give it its dark color.

How Diabase Forms

Diabase forms when magma pushes its way into cracks or spaces within other rocks deep underground. It doesn't erupt onto the surface like lava. Instead, it cools slowly, but not as slowly as rocks that form very deep, like gabbro. This medium cooling speed allows it to form crystals that are larger than those in basalt (which cools quickly) but smaller than those in gabbro (which cools very slowly).

• Dikes: Sometimes, magma fills a crack that cuts across layers of existing rock. When this magma cools, it forms a flat, wall-like rock body called a dike. Many dikes are made of diabase.
• Sills: Other times, magma squeezes between existing layers of rock, forming a flat, sheet-like body that runs parallel to the layers. This is called a sill. Diabase is also very common in sills.

Where is Diabase Found?

Diabase is found all over the world. It's a very common rock type. You can find large areas of diabase in places like:

• The Palisades along the Hudson River in the United States.
• Parts of Northern Ireland, like Fair Head.
• Many areas in Tasmania, Australia, where it forms tall, interesting columns.
• In Namibia, Africa, where it creates unique landscapes.

Because diabase is very hard and strong, it often forms hills, ridges, or cliffs that stand out from the surrounding softer rocks.

Uses of Diabase

Diabase is a very useful rock because of its strength and durability.

• Construction: It's often crushed and used as aggregate in road construction, railway ballast, and concrete. Its hardness makes it excellent for these purposes.
• Building Stone: Sometimes, diabase is cut and polished to be used as a decorative stone for buildings, countertops, or monuments. It can have a beautiful dark, speckled appearance.
• Landscaping: Its natural dark color and resistance to weathering make it popular for landscaping projects.

Images for kids

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  Fair Head, Northern Ireland, is made of diabase.

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  A diabase dike cutting through horizontal limestone beds in Arizona.

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  Diabase boulders at Devil's Den on the Gettysburg Battlefield, Pennsylvania.

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  Dolerite rocks and Quiver trees near Keetmanshoop in Namibia.

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  Dolerite forms tall vertical columns throughout Tasmania. These columns create steep vertical features through its alpine areas.

See also

In Spanish: Diabasa para niños