When magma cools off earth surface which type of crystalline structure is usually found?

When magma cools on the Earth's surface, it typically forms a fine-grained crystalline structure known as an aphanitic texture, as seen in volcanic rocks like basalt and rhyolite. This rapid cooling prevents the formation of large crystals, resulting in a more uniform, smaller grain size. In contrast, slower cooling beneath the surface leads to a coarse-grained texture, such as that found in granite.