In Earth Science, when magma takes hundreds of years to cool into rock, the mineral crystals within the rock most likely will be large. This slow cooling process allows for the minerals to grow and form larger crystals due to the extended period of time for the atoms to arrange themselves into a more organized structure.
Large mineral crystals indicate that the rock cooled slowly beneath the Earth's surface, providing enough time for the crystals to develop and grow. This type of rock with large crystals is known as intrusive or plutonic rock.
On the other hand, if the magma cools rapidly, the mineral crystals will be fine-grained, meaning they are smaller in size. Rapid cooling occurs on the Earth's surface or near it, resulting in rocks with small crystals known as extrusive or volcanic rocks.
