| Granite is igneous rock. It is light in color, but the grain | | | | Granite is found on every continent of the earth, |
| can be medium or coarse. The rock is composed | | | | especially in places where the earth has been worn |
| mainly of alkali feldspar and quartz and is easily | | | | away by erosion. It often forms the core of mountains |
| recognizable by the visible grains of the various dark | | | | that forceful pressures within the earth have pushed |
| minerals. Granite rocks are the most common of all | | | | upward. Sometimes bodies of granite are found in |
| crystalline rocks found on the surface of the earth. | | | | large outcroppings of rocks that are found in chimney |
| They are found all over the world, usually in great | | | | like and overhanging rock formations. The Appalachian |
| masses called batholiths that often extend over | | | | Mountain range in the United States is composed |
| thousands of miles. This is a popular material form use | | | | mostly of granite. It is also found in the Ozark |
| in monuments and buildings because of its hardness, | | | | Mountains, the Black Hills, and the front range of the |
| durability and the range of colors. | | | | Rocky Mountains. Granite is also produced in many |
| Composition of Granite | | | | states such as Georgia, California, Virginia, Minnesota, |
| Granite is composed mainly of potash, feldspar and | | | | South Dakota and the Carolinas. |
| quartz. The color of the rock varies from gray to red | | | | How Granite is Formed |
| and is usually determined by the amount of the potash | | | | Geologists have two different theories about how |
| feldspar. If there is a lot of glassy crystals in granite, it | | | | granite was formed. One theory says that granite |
| will tend to have a bluish color. Dark minerals, such as | | | | formed directly from molten lava. The other theory |
| hornblende, biotite mica and muscovite mica can | | | | states that it was formed as a result of the alterations |
| sometimes be found in granite. Some types of rock | | | | of other rocks and that granite is metamorphic rock, |
| that are commonly called granite contain different | | | | rather than igneous rock. |
| amounts of plagioclase feldspar. Rocks that contain | | | | Uses of Granite |
| about one-fifth of the amount of potash feldspar | | | | Granite has been used a building material for |
| relative to the amount of plagioclase feldspar is really | | | | thousands of years. In ancient Egypt, the obelisks were |
| granodiorite, rather than granite. Rocks that have the | | | | built from granite. Today, granite is used in building |
| same composition as granite, but have a very large | | | | monuments, curbs for roads, tombstones, and as a |
| amount of crystals are known as pegmatite. | | | | structural element in buildings. |
| Where Granite is Found | | | | |