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Rocks are the materials of which mountains, cliffs and the ground are made. Even sand, clay and soil are types of rock made from tiny particles. The processes that shape the rocks around us to form the landscape can take thousands or even millions of years. |
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All rocks can be divided into three main groups - igneous, sedimentary and metamorphic rocks - according to the way in which they were formed. Just as rocks are the building blocks of the landscape, minerals are the building blocks of rocks. Minerals are naturally occuring substances found in the ground that are not part of an animal or a plant. About 3,500 different minerals have been identified. Some rocks contain only one mineral, but most are a mixture of two or more. Minerals include familiar substances, such as quartz and gold, and less familiar ones, such as kyanite and pyrite. |
