Vesicular texture is avolcanicrock texture characterized by a rock being pitted with many cavities (known as vesicles) at its surface and inside.[1] This texture is common inaphanitic, or glassy,igneous rocks that have come to the surface of the Earth, a process known asextrusion. Asmagma rises to the surface the pressure on it decreases. When this happens gasses dissolved in the magma are able to come out of solution, forming gas bubbles (the cavities) inside it. When the magma finally reaches the surface as lava and cools, the rock solidifies around the gas bubbles and traps them inside, preserving them as holes filled with gas called vesicles.[2]
A related texture isamygdaloidal in which the volcanic rock, usuallybasalt orandesite, has cavities, or vesicles, that are filled with secondary minerals, such aszeolites,calcite,quartz, orchalcedony.[3] Individual cavity fillings are termedamygdules (American usage) or amygdales (British usage). Sometimes these can be sources of semi-precious or precious stones such as diamonds.
Rock types that display a vesicular texture includepumice andscoria.
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