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Mineral Composition
The lower part of the 'scheme' is where the minerals that make up the igneous rocks are found. Remember, the rocks are on top and the minerals are on the bottom.
The minerals on the left are found in the extrusive igneous rocks on the left.
The minerals on the right are found in the intrusive igneous rocks on the right.
If you are asked a question about an igneous rock be sure to select your answer from among the rocks at the top of the chart. But if you are asked about minerals found in igneous rocks, then be sure to select your answer from among the minerals at the bottom of the chart.
Keep in mind that there can be enormous variation even among rocks of the same type because they may contain different minerals in different proportions and they may form under very different conditions. This accounts for the thousands of varieties of granite, for instance which may all appear to be quite different but which are all still granite.
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