Which igneous texture is characterized by extremely rapid cooling?

The igneous texture characterized by extremely rapid cooling is glassy. This texture occurs when magma or lava cools so quickly that the atoms do not have time to arrange themselves into a crystalline structure. As a result, the rock that forms has a smooth, glasslike appearance, often with a lack of mineral grains. This type of cooling is typically seen in volcanic glass, such as obsidian, which can be formed when lava is ejected explosively and cools rapidly upon contact with air or water.

Other textures, like granular or fine-grained, are associated with slower cooling rates, allowing for the development of crystalline structures. The porphyritic texture features both large crystals and finer-grained matrices, indicating a two-stage cooling process where some crystals formed during slower cooling before the remaining material solidified rapidly. These distinguishing features of glassy texture, linked to its rapid cooling, help classify igneous rocks based on their formation conditions.