Why Does Basalt Have Smaller Crystals 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.

Why does basalt have smaller crystals than granite.

Basalt forms when magma cools and solidifies on the surface of the earth. This slow cooling gives time for crystals to grow making it more coarsely grained than an extrusive rock. Why does rhyolite 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.

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. Gabbro cooled slowly and is entirely composed of large larger crystals without any glassy or very fine grained rock material. Cools more slowly and crystals are bigger which means they are coarse grained. Basalt cooled quickly and is therefore fine grained to even glassy with or without phenocrysts individual large crystals.

Fossils are only found in. Basalt on the other hand has a smooth texture from rapid cooling usually by water. They cools so fast and that s why they have small crystals than granite. Basalt scoria andesitic diorite andesite granitic granite rhyolite pumice obsidian.

You may use your identification charts rhyolite cooled quicker than granite. This coarse grain makes granite a favorite of rock climbers. Under the ground so they cools slow and that s why they have large crystals. It mainly occurs on the floor of the ocean as magma solidifies quickly coming in contact with cool ocean water.

The difference is the texture. Granite is an intrusive rock that is formed when magma cools inside the crust. Crystals have more time to grow to larger size.