Why Does Basalt Have Smaller Crystals Than Granite

Crystals have more time to grow to larger size.

Why does basalt have smaller crystals than granite.

This slow cooling gives time for crystals to grow making it more coarsely grained than an extrusive rock. 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. Basalt on the other hand has a smooth texture from rapid cooling usually by water. 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.

This coarse grain makes granite a favorite of rock climbers. The difference is the texture. It mainly occurs on the floor of the ocean as magma solidifies quickly coming in contact with cool ocean water. Cools more slowly and crystals are bigger which means they are coarse grained.

Basalt forms when magma cools and solidifies on the surface of the earth. Under the ground so they cools slow and that s why they have large crystals. How can you distinguish basalt from a sill or buried lava flow. They cools so fast and that s why they have small crystals than granite.

Basalt scoria andesitic diorite andesite granitic granite rhyolite pumice obsidian. 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. Fossils are only found in. You may use your identification charts rhyolite cooled quicker than granite.

Gabbro cooled slowly and is entirely composed of large larger crystals without any glassy or very fine grained rock material. These extrusive rocks are formed from magma at or above the surface of the planet and generally display smaller mineral crystals or. Among other differences the nature of these rocks reveals that basalt is basic in nature whereas granite is acidic in nature.