Scoria

Scoria is a term used by geologists to describe an igneous rock containing many gas bubbles, or vesicules.

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Scoria forms when magma rich in dissolved gases is vented. As the magma encounters lower pressures, the gasses are able to escape and form bubbles. These bubbles are trapped when the magma cools and solidifies.

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Volcanic cones of scoria can be left behind after eruptions, usually forming mountains with a crater at the summit. An example is Mount Wellington, Auckland in New Zealand.

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Another material can be formed during burning eruption of a mud volcano, when heated mud forms scoria cones.

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Natural coal fires have also created large deposits of material which have erroneously been called scoria.

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Geologist: A geologist is a contributor to the science of geology, studying the physical structure and processes of the Earth. Their undergraduate training typically includes significant coursework in chemistry, physics, mathematics and possibly biology, in addition to classes offered through the geology depa...

Igneous rock: Igneous rocks are formed when molten rock (magma) cools and solidifies, with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks. This magma can be derived from either the Earth's mantle or pre-existing rocks made molten ...

Volcanic cone: Volcanic cones are among the simplest volcano formations. They are built by fragments (called ejecta) thrown up (ejected) from a volcanic vent, piling up around the vent in the shape of a cone with a central crater. Volcanic cones are of different types, depending upon the nature and size of the fra...