The Importance Of Rock And Rock Formation

1621 Words 7 Pages
While it may not seem like it, rocks and rock formation are a vital part of our day to day lives. Some geologists spend their lives studying these rocks to determine what rocks are in certain areas and how they formed. This information allows them to predict what is going to happen in the future as well as how the land got to be in the shape it is today. Experienced geologists can often know how a rock formed just by looking at it, but inexperienced geologists can easily do the same, if they know and keep in mind how certain types of rocks form. Igneous rocks have different textures, compositions, and formation locations which can be used to infer how and where a specific rock formed. With igneous rocks, texture does not refer to roughness or smoothness of the surface. “Texture” instead refers to crystal size, shape, and arrangement within the rock. Texture is determined by how long the lava or magma takes to cool (Rutzky). Rocks with larger crystals had longer cooling times, giving the hot minerals time to crystallize and grow. On the flip side, rocks with small …show more content…
Composition is the rocks chemical and mineral make up. The exact composition of a rock can only be determined by advanced geologic equipment. Luckily, however, geologists without those resources can determine the composition of a rock (felsic, intermediate, mafic, or ultramafic) through color identification. Generally, felsic and intermediate rocks will have much lighter colors while mafic and ultramafic have very dark shades. This is caused by the amount of silicates in the rock. Mafic and ultramafic rocks have less silicates while felsic rocks are composed primarily of silicates. Intermediate rocks are a midpoint between felsic and mafic, meaning they have more silicates than mafic and ultramafic rocks, but not as much as felsic rocks (Reynolds 113). One exception to these guidelines is obsidian: a dark colored felsic rock

Related Documents