Many people eat minerals, but not many people would eat a rock. Would you eat a rock? If you eat salt or take iron tablets, you are consuming a part of a rock. Although there is a relationship between rocks and minerals, they are different.
Minerals are defined as naturally occurring, or not made by man, solids with a definite chemical composition and a specific crystalline structure. Minerals can be inorganic which means they are not derived from living cells or they can be organic in origin, in other words they are derived from living cells such as those found in food.
One of the most frequently consumed minerals is salt. If you look at a grain of salt under a microscope the crystal like structure is easily seen and there are beautiful salt crystal formations found in Death Valley.
Another mineral that is necessary for life is iron and is consumed in infinitesimal amounts. For red blood cells to transport oxygen throughout the human body, iron is essential to hemoglobin molecules. If a person does not get enough iron in their diet they can become anemic. Interestingly, the mineral iron is also used in the production of metal which bears its name. Small amounts of other minerals are also consumed in many everyday foods.
Because minerals form in block like structures it is easy to see how some gems could form. When you look at a diamond, amethyst or emerald you are looking at a crystallized mineral form that is very hard. Yet some minerals are very malleable and soft, such as gold or copper, which are made up of a single element. Most quality jewelry is entirely made up of minerals.
So what is the relationship between minerals and rocks and how are they different? Minerals are the ingredients of rocks. Although the crystal like structures of minerals are pretty, when they combine to form a rock they usually lose their individual beauty. There are three types of rocks and each are composed of different mineral elements.
Igneous rocks are formed as molten rock brought up through the earth’s crust cools. Granite is an example of igneous rock and some of the minerals that make up granite are quartz, feldspar and plagioclase. Sedimentary rocks are formed as mineral, both organic and inorganic, sediments settle and are compressed by pressure. Metamorphic rocksare rocks that have undergone a metamorphosis from older igneous or sedimentary rocks. They also can be reformed metamorphic rocks that have changed due to the heat produced from the movement of the tectonic plates of the earth.
The most important difference between minerals and rocks is their use as building materials by man. It would be futile to construct a building out of minerals since they are so tiny. On the other hand, the size of rocks that can be quarried make ideal building blocks to build monuments that will last for centuries like the Great Pyramid of Gaza or the Mayan temples of Mesoamerica.