Knowing how a geologist classifies rocks is important if you want to transform a random group of rock specimens into a true collection. Igneous rocks are formed from melted rock that has cooled and solidified.
Why Do Geologists Classify Rocks?
Rocks are a fundamental part of our world, but did you know that geologists classify rocks? Rocks are classified according to their physical and chemical properties, which can vary significantly from rock to rock. By classifying rocks, geologists can better understand the composition, structure and distribution of rocks in different locations, as well as their origin and age.
Geologists classify rocks into three distinct categories: igneous, sedimentary and metamorphic. Igneous rocks are formed from the cooling and solidification of magma, which is molten rock that originates deep within the Earth’s crust. These rocks comprise quartz, feldspar, mica, and amphibole minerals.
Sedimentary rocks are formed when sediment particles—such as sand, mud, silt, and gravel—are deposited, compressed, and cemented together. The particles may have been eroded from preexisting rocks or resulted from weathering and decomposition of organic materials. These rocks are composed of sedimentary particles, such as clay, sand, silt, and pebbles.
Metamorphic rocks are formed when existing rocks are subjected to intense heat and pressure. These rocks are characterized by an inter