Minerals are the building blocks of rocks. All rocks, igneous, sedimentary, or metamorphic, are composed of minerals. A mineral is a chemical compound that occurs naturally. Each different mineral is made up of crystals of a particular chemical. Minerals can be identified by thier hardness, color, density, the way they reflect light and the way they break. Sometimes, using a hand lens you can even identify the shape of the individual crystals of a mineral within a rock.
Rock forming minerals
Rocks are made up of mineral grains. The most common minerals that make up igneous rocks include quartz, plagioclase, and olivine. Augite is found in metamorphic rocks. Dolomite makes up limestone sedimentary rocks.
What minerals are made of
About 90 different chemical elements are found naturally in the Earth's crust. But almost 99% of all minerals are made of just 8 elements: oxygen, silicon, aluminum, iron, calcium, sodium, potassium, sodium, and magnesium. Some minerals, such as gold and diamond, consists of a single element. These minerals are called native elements.
How minerals are formed
All minerals are originally formed from hot magma. When the magma cools, crystals of minerals appear. These first crystals may sink in the magma so that the composition of the magma changes with depth. Thus a sequence of minerals is formed in the rocks as the magma cools.
| Diamond | 10 |
| Corundum | 9 |
| Topaz | 8 |
| Quartz | 7 |
| Orthoclase (Feldspar) | 6 |
| Apatite | 5 |
| Fluorite | 4 |
| Calcite | 3 |
| Gypsum | 2 |
| Talc | 1 |
Mohs Hardness Scale
Gypsum is a soft mineral, hydrous calcium sulfate or CaSO4ยท2H2O. Gypsum is the standard for hardness degree 2 on the Mohs mineral hardness scale.
