Rock Gallery

Rocks come in many different shapes, sizes, colours and textures. Some are harder than others. Some are very precious while others are not. However, no matter what qualities a rock possesses, it can be placed into one of the three major classes of rock. Here are a few examples of igneous, sedimentary and metamorphic rocks. Click on an image to start the slideshow.

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  photo by Marcus Revertegat

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  Obsidian (volcanic glass) is an extrusive igneous rock formed when lava cools very rapidly.

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  Volcanic agglomerate (extrusive igneous rock)

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  Basalt (extrusive igneous rock)

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  Biotite granite (intrusive igneous rock)

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  Adamellite granite (intrusive igneous rock)

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  Pegmatite is an intrusive igneous rock with very large crystals

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  Dolerite (intrusive igneous rock)

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  Gabbro (intrusive igneous rock)

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  photo by yeowatzup

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  Shale (sedimentary rock formed from the compaction of tiny particles)

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  Sandstone (sedimentary rock formed when sand sized particles are cemented together)

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  Red sandstone (sedimentary rock)

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  Limestone (sedimentary rock formed mainly from calcium carbonate)

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  Chalk is a soft porous sedimentary rock composed mainly of calcium carbonate

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  Conglomerate is sedimentary rock made up of large sediments such as pebbles which have been cemented together

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  Breccia is sedimentary rock made up of broken fragments of rock which have been cemented together

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  photo by GOC53

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  Gneiss is a metamorphic rock formed when rocks are subjected to very intense heat and pressure.

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  Schist is a metamorphic rock formed when rocks are subjected to intense heat and pressure.

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  Slate is a metamorphic rock formed when shale is subjected to intense heat and pressure.

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  Marble is a metamorphic rock formed when limestone is subjected to intense heat and pressure.