Fact 1: Rocks are of three types called: igneous, sedimentary, and metamorphic. Many pieces of rock and soil that are broken from larger rocks slowly settle down into layers. In the course of time, these layers will come together and form a hardened rock called sedimentary rock.
Fact 2: Sedimentary rocks are formed in the places where large bodies of water existed or currently exist. They are formed in the areas of lakes and oceans. Some of the examples of sedimentary rocks are limestone, shale, coal, sandstone, chalk, and layered.
Fact 3: If the molten rock cools and becomes hardened, it leads to the formation of igneous rocks. The lava from volcanoes and the magma in the Earth cools gradually and results in the formation of igneous rocks. The examples of igneous rocks are: granite, obsidian, basalt, shiny, quartz, and pumice.
Fact 4: Any rock type that is modified due to heat and pressure deep inside the Earth is categorized as metamorphic rock. Metamorphic rocks are formed deep inside the Earth and they are very often hard.
Fact 5: Metamorphic rocks consist of crystals. Other examples of this rock type are: slate, schist, marble and gneiss.
Fact 6: Rocks will start with one form and change in course of time into another rock type. The changes will occur very slowly and will not be visible.
Fact 7: Heat and pressure change the rocks, they get broken down later and are moved by erosion. The weathering of rocks and their erosion takes place in a few thousand years. The process of changes occurring in the rock is called a rock cycle.
Fact 8: The weathering of rocks is a process where the rocks break down into small pieces. This process is caused by ice, running water, wind, rain, chemicals, plant roots, thawing, and freezing.
Fact 9: The process of movement of rock pieces from one place to another is called erosion. The erosion of rock pieces are results due to rain, gravity, wind, running water, waves, and ice.
Fact 10: Rocks comprise of one or more minerals.