Why Does Basalt Have Smaller Crystals Than Granite

Basalt forms when magma cools and solidifies on the surface of the earth.

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. 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. 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.

How can you distinguish basalt from a sill or buried lava flow. Among other differences the nature of these rocks reveals that basalt is basic in nature whereas granite is acidic in nature. Basalt scoria andesitic diorite andesite granitic granite rhyolite pumice obsidian. Basalt on the other hand has a smooth texture from rapid cooling usually by water.

Fossils are only found in. This coarse grain makes granite a favorite of rock climbers. It mainly occurs on the floor of the ocean as magma solidifies quickly coming in contact with cool ocean water. 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 rhyolite have smaller crystals than granite. 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. You may use your identification charts rhyolite cooled quicker than granite. These extrusive rocks are formed from magma at or above the surface of the planet and generally display smaller mineral crystals or.

Crystals have more time to grow to larger size. Under the ground so they cools slow and that s why they have large crystals. The difference is the texture.