Explore kinds of rocks. Rocks are fascinating things because they take a long time to form. Who knew that the piece of pumice of limestone in lawns and gardens may actually have a rich history? Many scholars are interested in the various types because they inadvertently tell of the earth’s history and the changes in the earth’s surface when these rocks where formed.
Pumice (Igneous Rocks)
Igneous kinds of rocks are also called pumice, and are formed from solidifying magma from volcanoes. Igneous rocks may crystallize, but many types are created without the process of crystallization. Many of these crystals are visible to the unaided human eye. The magma from which these rocks originate originate from the partial melting of the rocks in the lower layers ot the earth, particularly the mantle and crust. Melting of the rocks inside the earth can be caused by pressure and temperature modifications. Variations in the chemical composition of the earth’s core may also lead to melting.
Igneous rocks can further be categorized in accordance with their mineral and chemical compositions, where they are found and their texture. The size of the particles and minerals in igneous rocks are telling of their history, specifically the environment where they were formed. Some kinds of rocks are from volcanoes in cooler regions, and others are from volcanoes located in the tropics. The minerals that typically comprise these rocks include iron and magnesium, and the common crystals interspersed among these minerals are quartz, pyroxenes and micas.
Limestone (Sedimentary Rocks)
Sedimentary rocks are more common than igneous rocks because they are found everywhere, especially in hilly locations and those near mountains. The name of these rocks is derived from sedimentation, a common process wherein small particles collect and coagulate to form a solid mass. Many of these kind of rocks can be found in waterbeds in shallow streams, and also in sites of rock erosion and weathering such as the beach. Detritus from various sources collect in a particular area consistently. Heat, cold weather and other changes in environmental conditions lead to the solidification of these sediments to form different kinds of rocks.
These rocks are not chipped off from bigger rocks, and the mineral composition may vary. The source of sediments deposited in the general area define the type of sedimentary rock prevalent in that area. When limestone collectors and builders flatten a hill, the sedimentary rocks underneath the greenery are exposed. While these kinds of rocks are expected to be plentiful in various areas, they are still not as numerous as pumice and marble. In fact, sedimentary rocks comprise the layer over the earth’s crust, which comprise mainly marble and pumice kinds of rocks.
Marble (Metamorphic Rocks)
Metamorphic rocks are extremely rare because they come from the further transformation of the other two kinds of rocks, igneous and sedimentary. Some kinds of metamorphic rocks are also from older metamorphic rocks, although the present version is chemically and physically different. To form a metamorphic type, extreme heat and pressure must be present. The physical and chemical variations in the original sedimentary or igneous rock culminate into the formation of a rock type that does not resemble the original rock.