Why Does Basalt Have Smaller Crystals Than Granite

Basalt is basic and contains a substantial amount of olivine whereas granite is acidic and is rich in quartz basalt is an extrusive igneous rock with small mineral crystals formed when magma.

Why does basalt have smaller crystals than granite.

It mainly occurs on the floor of the ocean as magma solidifies quickly coming in contact with cool ocean water. These extrusive rocks are formed from magma at or above the surface of the planet and generally display smaller mineral crystals or. Under the ground so they cools slow and that s why they have large crystals. Why does rhyolite have smaller crystals than granite.

Basalt cooled quickly and is therefore fine grained to even glassy with or without phenocrysts individual large crystals. Gabbro cooled slowly and is entirely composed of large larger crystals without any glassy or very fine grained rock material. You may use your identification charts rhyolite cooled quicker than granite. If magma cools quickly for example when basalt lava erupts from a volcano then many crystals form very quickly and the resulting rock is fine grained with crystals usually less than 1mm in size.

Basalt forms when magma cools and solidifies on the surface of the earth. Among other differences the nature of these rocks reveals that basalt is basic in nature whereas granite is acidic in nature. This slow cooling gives time for crystals to grow making it more coarsely grained than an extrusive rock. How can you distinguish basalt from a sill or buried lava flow.

Yes because granite is a slow cooling rock therefore the crystals have a lot of time to form while basalt is a fast cooling rock therefore thecrystals don t have much time to form and develop. They cools so fast and that s why they have small crystals than granite. Cools more slowly and crystals are bigger which means they are coarse grained. Basalt on the other hand has a smooth texture from rapid cooling usually by water.

This coarse grain makes granite a favorite of rock climbers. Granite is an intrusive rock that is formed when magma cools inside the crust. Basalt scoria andesitic diorite andesite granitic granite rhyolite pumice obsidian.