The non – metallic minerals are those minerals that have no metallic properties and also not serve as a source or ore for metal production.
In general, they are minerals that do not contain metals of industrial interest as part of their composition. However, they can contain other metals such as some alkali metals that are of less economic value.
Non-metallic minerals are very varied and have very diverse compositions, which is why they find different applications in industries such as construction, energy production, the production of ceramic materials, etc.
Characteristics of non-metallic minerals
- They are thermal and electrical insulators.
- They do not have a metallic luster.
- They are not malleable or ductile materials.
- Some are translucent with a low refractive index, while others are opaque.
- In general, they are refractory materials that are highly resistant to high temperatures and attack with chemical substances.
- They have very varied characteristic colors.
- Some have special optical and electrical properties that make them useful for making watches as well as high-intensity lasers.
- Some are very soft materials, while others like diamond are some of the hardest natural materials known to man.
- They do not decompose when melted.
- They are generally found in young geological formations in sedimentary rocks.
- They are very abundant in the earth’s crust. In fact, after fossil fuels, non-metallic minerals are the second most important source of mineral wealth in the world.
Types of non-metallic minerals
According to the area of their application, non-metallic minerals are classified into two large groups:
- Agrochemicals and raw materials for chemicals.
- Geological building materials.
Agrochemicals and raw materials for chemicals
These non-metallic minerals are some of the most important in the world, as they form the basis for the preparation of chemical fertilizers that help balance the nutrient content in agricultural production lands.
Mineral agrochemicals contain elements such as nitrogen, phosphorus, potassium, calcium, and sulfur in varying amounts. An example of a highly important agrochemical is apatite, a mineral that serves as a source of phosphorus.
There are also a large number of halide minerals that are obtained from mines (such as salt mines that mainly produce sodium chloride) and minerals obtained by evaporation from sea water. The latter are the main source of potassium in the group of agrochemical non-metallic minerals.
Geological building materials
Geological building materials include cement, lime, plaster, marble, sand, rock, and all those materials other than metals and wood with which humans build our houses and buildings. Sand and gravel for construction, called aggregates, are the most exploited minerals on the planet.
Annually, 50 billion metric tons of this non-metallic mineral are extracted from the earth’s crust, almost 16 times more than the production of iron and steel that constitutes the main metallic mineral exploited by the mining industry. It is also 8 times greater than the production of cement, which is the second most exploited non-metallic mineral.
This is a large group of non-metallic minerals and includes:
- Cements: they consist of mixtures of sandstones and dolomites with marls and clays. It is a crushed product in the form of a very fine powder that reacts with water and hardens.
- Aggregates (sand and gravel): formed mainly by silicates of different types crushed to form small particles. They contain many other types of minerals such as quartz.
- Alabaster: it is a calcium sulfate dihydrate.
- Clays: they are an important group of minerals composed of hydrated aluminum silicates and a laminar structure. They are used in the manufacture of ceramic materials.
- Glasses: they are a family of minerals produced by the fusion of silica sand, limestone, sodium carbonate and feldspar. It is an essential material in construction.
- Asbestos or asbestos: it is a material with a structure in the form of microscopic fibers. It is a strong abrasive material and is also highly refractory, lightweight and is an excellent thermal insulator.
Non-metallic mineral applications
As could be seen from the general classification of non-metallic minerals, the two main applications of these minerals are in the agricultural industry and in construction . However, a large number of additional industries depend on these minerals:
From the manufacture of auto glass to brake pads (many of which contain asbestos), non-metallic minerals provide many indispensable materials for automobile construction.
Among the minerals produced by evaporation of seawater are halides, among which the most important is sodium chloride or common salt. This forms an essential part of our diet. Other important minerals include calcium carbonates and other minerals of phosphorus, calcium, and magnesium that serve as supplements and fortifiers for many food products.
Metallic minerals may provide the metals that conduct electricity, but non-metallic minerals, especially clays, cements and glasses, are used to make insulating refractory pieces to protect electrical connections and prevent short circuits in high voltage electrical networks. .
All precious and semi-precious stones used in jewelry, from diamonds, rubies, and sapphires down, are non-metallic minerals.
Examples of non-metallic minerals
It is a microcrystalline variety of silica, which can have different impurities that give it characteristic colors.
Red sedimentary rock with characteristic marks that can be polished to a special shine.
A type of white clay present in kaolinite. It is frequently used in papermaking to make sheets whiter and more opaque.
It is a calcium carbonate mineral that is used to make glass, paints, fertilizers, and even some metals.
It is a very fine form of limestone. It is used to make blackboard chalks due to its smoothness and ability to leave scratches on rough surfaces.
It is a mineral with a laminar structure that has the property of being a great electrical insulator. It is used as insulation in the construction of high voltage and high power machines .
It is a mineral that forms rocks and large crystals of varied colors, depending on the impurities present. It is an extremely hard material, almost as hard as diamond and is used as an abrasive agent.