When we walk on the earth’s surface we hardly pay attention to the ground we walk on, sand, earth, stones … However, if we take a closer look, we will notice small differences, at first glance, in size, color or texture. This is due to the fact that the soil is made up of different materials, whose differences in origins and composition are responsible for the variations in the characteristics of the terrain.
What is a mineral
We call mineral a natural and inorganic solid material with a specific chemical composition and a defined crystalline structure . Its origin depends on the chemical elements and the physical, chemical and thermodynamic characteristics of the natural system in which its formation takes place, regardless, unlike rocks, geological phenomena. Minerals can be classified based on their chemical composition and internal structure in:
- Native elements.
- Oxides and hydroxides.
- Carbonates, nitrates and borates.
- Sulfates and chromates.
- Volframates and molybdates.
- Phosphates, arsenates and vanadates.
Most minerals are made up of several chemical elements , which can be located in two ways:
- Messy : the components are not in defined geometric shapes, giving the mineral an amorphous structure, such as natural glasses.
- Orderly : the components have a defined and ordered geometric shape. In these cases they are said to have a crystalline structure and if this is seen with the naked eye it is called a crystal. Most of the minerals are crystals.
It is important to emphasize that minerals must have a defined chemical composition . For example, graphite and diamond have the same composition, however, as their molecular arrangement is different, two different minerals are considered.
Rocks are the most common and abundant material on Earth . They are the result of certain meteorological phenomena, so that their size, shape and composition are a reflection of the geological processes that created it. This fact makes them the subject of numerous studies and allows researchers to obtain the information necessary for understanding our planet and for application in the search for mineral and energy resources.
Geologists divide rocks into three large groups : igneous, sedimentary, and metamorphic.
- Igneous rocks : formed when magma (molten rock) cools and solidifies. As magma cools, crystals of various minerals form, so if it cools inside the crust, the process is slower and the size of the crystals will be larger than if it cools in one way. abrupt, as occurs in volcanic eruptions. Igneous rocks that form on the earth’s surface are called volcanic and are usually fine-grained.
- Sedimentary rocks : they are formed from the compaction or cementation of layers of sediments, which are the remains of rocks that have been detached due to weathering processes.
- Metamorphic rocks : they are produced from igneous, sedimentary, or even other metamorphic rocks. Through changes in temperature, pressure or chemical alterations, the modification of the mother rock occurs, which leads to the formation of a new rock.
Rocks, in turn, are made up of heterogeneous mixtures of other materials, generally grains or crystals of one or more minerals. When it is composed of a single mineral it is known as monominerálica rock, whereas, when it is composed of several types of minerals it is called polyminerálica.
Thus, we can say that while minerals are stable in their atomic number and chemical formula, rocks are made up of a combination of mineraloids or minerals.
What is a crystal
Crystals are homogeneous solid materials with a defined chemical composition and an ordered internal structure that give rise to very striking geometric shapes, being recognized, most of the time, for their beauty and symmetry.
These formations are due to the fact that, when a crystal originates, a process known as crystallogenesis, the chemical elements come together to form a crystal lattice under specific conditions of time, space, pressure and temperature.
Depending on how these crystallization factors are combined we will have:
- Macromineral substances : crystals can be seen with the naked eye.
- Microcrystalline substances : crystals are recognized by using a microscope.
- Cryptocrystalline substances : crystals recognizable by X-ray diffraction.
Therefore, we can say that crystals are a kind of mineral, in fact, most minerals are crystals.