Minerals and rocks can be identified in different ways. Minerals are naturally occurring, homogeneous solid substances that are generally inorganic. Minerals are also crystalline solids with a definite chemical composition. By calling a substance inorganic, that substance would not be formed by living things such as plants or animals. Minerals are the building blocks of rocks. Minerals can be identified through their physical and chemical properties. Almost all rocks are made up of one or more minerals and are classified based on how they formed. Igneous rocks are made up of magma or lava that has cooled and solidified. Another kind of rock, known as sedimentary, results from the compaction and cementing of layers of sediment. The final type of rock, metamorphic, forms when other rocks are exposed and changed by heat or pressure. Rocks can be classified based on grain size and whether they are felsic or mafic. When determining whether a substance is a rock or mineral it is important to examine the substance closely. Any substance that does not appear to be a uniform mineral would be a rock. To determine what type of rock further examination would be required. If fossils or plant remains are visible then it can be concluded that the particular rock is sedimentary. If small rocks and rounded pebbles are visible then the rock is conglomerate. A rock that is igneous may come in a variety of colors and can be composed of grains from course to glassy. Lastly, metamorphic rocks may be spotted if banding is visible. This would make a rock appear in light and dark layers. In trying to tell a mineral apart from a rock a problem may occur. It is important not to only base a rock or mineral on its color because color changes from sample to sample.
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