Igneous textures

When extrusive rocks make contact with the atmosphere they cool quickly, so the minerals do not have time to form large crystals.

Pegmatitic texture occurs during magma cooling when some minerals may grow so large that they become massive (the size ranges from a few centimetres to several metres).

Pegmatites are most commonly formed as coarse-grained igneous rocks of granitic composition, containing large clasts of gemstones such as amazonite, garnet, and topaz.

The minerals in a phaneritic igneous rock are sufficiently large to see each individual crystal with the naked eye.

Pyroclastic (pyro = igneous, clastic = fragment) textures occur when explosive eruptions blast the lava into the air resulting in fragmental, typically glassy material which falls as volcanic ash, lapilli, and volcanic bombs.