So, what is a "rock"? Rocks are naturally occurring. Sometimes objects look like rocks, but they are actually man-made, like concrete. Rocks have mixtures of minerals in them or perhaps one main type of mineral but with various other substances mixed in. Limestone, for example, contains the mineral calcite which has the chemical calcium carbonate (CaCO3) as the primary component. Sandstone contains the mineral quartz composed of silicon dioxide (SiO2).
When you find a rock, it is important to note where you found it. That can be a really great clue about what kind of rock it is. Some kinds of rock are much more common in certain areas. In the state of West Virginia, sedimentary rocks are the most common. The main types of sedimentary rock found in West Virginia are limestone, sandstone, and shale.
Igneous and metamorphic rock types are not commonly found in West Virginia. The igneous rocks are formed from magma or lava from volcanoes. Metamorphic rocks are formed from either igneous, sedimentary, or other metamorphic rocks. They are changed by heat and/or pressure. Notice how the word metamorphic is similar to the word metamorphosis? The rock has changed, just like caterpillars to butterflies or tadpoles to frogs!
A mineral is to a rock as a tree is to a _____. Can you fill in the blank? Sure, "forest" is the answer! As it turns out, minerals make up rocks. Sometimes there are different proportions of minerals in a rock. There may be only one main chemical component in a mineral, however. A mineral is defined by its chemical composition and by the fact that it must be solid, naturally occurring, crystalline, and inorganic (not containing material that was once alive). Minerals are found all around us. Can you think of some examples of minerals?
Several kinds of minerals that we carry at SMART Centre Market are: