Rocks are part of Earth’s crust. People use them to build houses, roads, and statues. But did you know you can learn a lot about a rock just by looking at it? You don’t need fancy tools. You only need your eyes and hands. You can tell what kind of rock it is by checking its color, texture, and shape.
Color Tells a Story
Color can show what the rock is made of. If a rock is light, it may have quartz or feldspar. These are minerals found in igneous rocks like granite. If the rock is dark, it may have iron or magnesium. These are found in basalt, another kind of igneus rock. Some rocks can even be green or pink.
Example: A sandstone rock is often red or yellow. That is from iron in the sand. It rusts, like metal.
Texture Shows the Parts
Texture means how the rock feels and looks. Some rocks are rough. Others are smooth. You can also look at the size of the grains.
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If the grains are big, it may be a slow-cooled rock, like granite.
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If the grains are small, it may be fast-cooled, like rhyolite.
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If you see layers, it may be a sedimentary rock like shale.
Chalk is a soft rock. You can scratch it easy. That’s how we know it is made from tiny sea animals. That is called a fossiliferus rock.
Shape Gives Clues
The shape can help too. If a rock is round, water may have moved it over time. If it is jagged, it may have just broken off a larger rock.
Rocks shaped by water are called river rocks. They are smooth and flat. Rocks broken by glaciers can be sharp and big.
What Other People Have Found
Geologests study rocks for their jobs. They look at rocks from mountains, rivers, and deserts. They use tests, but they also use their eyes and hands.
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Students in Arizona found that pink granite has feldspar and quartz.
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Hikers in Canada found black basalt near volcanoes.
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Farmers in France use limestone for bricks. It’s easy to cut.
Each group used color, texture, and shape to tell what the rock was.
Some Key Points
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Rocks with shiny bits often have mica.
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Rocks with bubbles are often made from lava.
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Rocks that break in layers may be sedimentery.
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White rocks often have lots of quartz.
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Gray rocks may be made from clay.
Final Thought
You don’t need to be a rock sientist to know about rocks. You only need to look close. Use your hands. Use your eyes. Rocks have their own tale to tell.