\u00a9 2021 wikiHow, Inc. All rights reserved. Read the descriptions in your lab manual or textbook for the source rock of each of the metamorphic rocks that you identify. This image is not<\/b> licensed under the Creative Commons license applied to text content and some other images posted to the wikiHow website. Metamorphic rocks are rocks that have undergone a change from their original form due to changes in temperature, pressure or chemical alteration. A gneiss rock will have a grey hue to it overall, with the dark and light strikes cutting through the gray coloration. Metamorphism also happens when rocks are buried deeply during the process of mountain building… The pre-existing rock is called either the parent rock or the protolith. The first step involves determining the texture of your unknown rock sample. Examples of complete descriptions of nonfoliated metamorphic rocks include nonfoliated, medium grained for quartzite, or nonfoliated, coarse grained for marble. For example, when you break granite apart, you get small pieces of quartz (clear), feldspar (pink or white), and mica (black). Illustrate how the three different types of rocks can change into another type of rock. So a lot of times a metamorphic rock will kinda look like a sedimentary rock, but it has been partially melted and deformed. Start by identifying and list all visible minerals present in the rock. This video discusses how to identify a metamorphic rocks: Contribute! The position of the minerals in metamorphic rocks is often the most important clue in identifying such rocks. wikiHow, Inc. is the copyright holder of this image under U.S. and international copyright laws. These parent rocks can be any type of rock, meaning they can be igneous, sedimentary or even other metamorphic rocks. The term texture refers to the size, shape, and boundary relationships of the minerals, particles, and other substances that make up a rock. This image is not<\/b> licensed under the Creative Commons license applied to text content and some other images posted to the wikiHow website. By studying metamorphic rocks, scientists can gain insight into the conditions inside the Earth during the metamorphic process. Two common non-foliated metamorphic rocks are marble and quartzite. The layers in slate are not formed from sedimentation, but from the organization of crystal molecules into a straight line under immense pressure. As you know, they are arranged in bands, or layers. This image is not<\/b> licensed under the Creative Commons license applied to text content and some other images posted to the wikiHow website. The texture can be foliated or nonfoliated. Rocks are made up of one or more minerals. Because they start as other rocks, there are many types. Determining whether a rock is metamorphic, as opposed to igneous or sedimentary, can be difficult. Metamorphic rocks like granite don’t have bands, but they do have remarkably concentrated amounts of crystals. Identifying Metamorphic Rocks -- designed for the introductory-level student in a physical geology class AFTER watching Identifying Minerals, Identifying . Foliation Foliation is an arrangement … There are only two metamorphic rock textural types, foliated and nonfoliated. In this texture the mineral crystals in the rock have grown in many directions and do not show alignment. Rocks without distinct alternating bands of light and dark minerals are described a nonlayered, whereas rocks with alternating bands of dark and light minerals are described as layered. Layered is also referred to as gneissic foliation. Marble is noticing the large crystals that seem randomly distributed, since it is a particularly tricky rock but... Have luster or shiny grains new rocks 12 references cited in this texture, the pieces are different from other... 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