Igneous Rocks With Large Crystals

The size of the crystals depends on how quickly the molten magma solidified.

Igneous rocks with large crystals.

Igneous rocks are of two types intrusive plutonic rocks and extrusive volcanic rocks. Rapid cooling results in smaller crystals while slow cooling results in large crystals. The large grains are called phenocrysts and rock with phenocrysts is called a porphyry that is it has a porphyritic texture. What are igneous rocks.

Intrusive igneous rocks are formed when the magma cools off slowly under the earth s crust and hardens into rocks. Examples of intrusive igneous rocks are diabase diorite gabbro granite pegmatite and peridotite. Igneous rocks are formed from the solidification of molten rock material. Igneous rocks contain randomly arranged interlocking crystals.

Igneous rocks that are formed underground are called intrusive igneous rocks. There are two basic types. Igneous rock derived from the latin word ignis meaning fire or magmatic rock is one of the three main rock types the others being sedimentary and metamorphic igneous rock is formed through the cooling and solidification of magma or lava the magma can be derived from partial melts of existing rocks in either a planet s mantle or crust typically the melting is caused by one or more of. They are characterized by large crystals mostly visible with the naked eye.

In many igneous rocks large mineral crystals float in a fine grained groundmass. Phenocrysts are minerals that solidified earlier than the rest of the rock and they are important clues to the rock s history.