What Is Plutonic Rocks?
Plutonic rocks are igneous rocks that solidified from a melt at great depth. The name "plutonic" refers to Pluto, Roman god of wealth and the underworld.
The main way to tell a plutonic rock is that it's made of tightly packed mineral grains of medium size (1 to 5 millimeters) or larger, which means that it has phaneritic texture. In addition, the grains are of roughly equal size, meaning that it has (equigranular or granular texture). Finally, the rock is holocrystalline—every bit of mineral matter is in a crystalline form and there is no glassy fraction. In a word, typical plutonic rocks look like granite. They have large mineral grains because they cooled over a very long time period (tens of thousands of years or longer), which allowed
The main way to tell a plutonic rock is that it's made of tightly packed mineral grains of medium size (1 to 5 millimeters) or larger, which means that it has phaneritic texture. In addition, the grains are of roughly equal size, meaning that it has (equigranular or granular texture). Finally, the rock is holocrystalline—every bit of mineral matter is in a crystalline form and there is no glassy fraction. In a word, typical plutonic rocks look like granite. They have large mineral grains because they cooled over a very long time period (tens of thousands of years or longer), which allowed