Myths and legends

What are minerals in simple words?

Minerals are natural bodies of natural origin. They are formed as a result of various physical and chemical processes on the surface or in the interior of the Earth. All minerals are currently or were once in a crystalline state. They can exist in either a solid, liquid (water, mercury) or gaseous (methane, carbon dioxide) state. The word “mineral” is of Latin origin and is derived from “minerale”, which means “ore”. Minerals are homogeneous in physical and chemical composition and are components of rocks, meteorites, and ores. The term “mineral” is sometimes used instead of the scientific term “mineral species” or “mineral variety.” A mineral species is the commonality of all mineral samples, having a common chemical composition and crystalline structure, i.e. commonality of specific samples. A variety is samples that are united in chemical composition and crystal structure, but have large differences in morphological features (color, grain, etc.). So, chalcedony, amethyst, crystal, citrine are varieties of the quartz mineral.

Formation of minerals

Minerals are formed either in the earth’s crust or on the surface. Formation processes are of one of three types:

  • Endogenous (deep). In this case, the formation of minerals occurs deep underground. Molten silicate rocks (magma), flowing into the thickness of the earth’s crust from the underlying layers, solidify. The gases and aqueous solutions released during this process collect in voids and cracks. This is how new minerals appear.
  • Exogenous (superficial). This type of process is characterized by the fact that the formation of new minerals occurs on the earth’s surface: in places of contact of the lithosphere with the hydrosphere, biosphere and atmosphere. Processes such as weathering and the formation of rocks due to the vital activity of organisms take place here (for example, the formation of shell rock from the mineralized remains of marine animals).
  • Metamorphic. Geological processes constantly occur in the earth’s crust, which cause the formation of new minerals. For example, sedimentary rocks of biogenic origin may end up in the lithosphere. There they are exposed to high temperature and pressure. This is how marble is made from limestone. Or vice versa, during a volcanic eruption, magma reaches the surface, flows out, solidifies and undergoes weathering and other exogenous changes.

Mineral classes

The world generally accepted classification of minerals was developed by the IMA (International Mineralogical Society). The basic unit of classification is the class. Classes include families, subclasses, groups and supergroups. Basically, the classification is based on chemical properties and includes the following classes:

  • Sulfides (arsenides, antimonides, selenides, bismuthides, telrides, as well as the pyrite-marcasite family). This is a group of sulfur compounds of 250 minerals. Examples: cinnabar, copper and iron pyrites.
  • Sulfates, derivatives of sulfuric acid with low hardness and non-metallic luster: Glauber’s salt, gypsum, anhydrite.
  • Sulfosalts,
  • Halides. More than 100 minerals, fluoride, chloride and other halogen compounds: fluorite, sodium chloride, sylvite.
  • Oxides (includes spinel and hegmobite supergroups) and hydroxides. These two classes make up up to 17% of the entire earth’s crust. Of this, 12% is quartz. In addition to it, oxides and hydroxides of silicon and metals combine many minerals of low and high density: bauxite, corundum, magnetite, hematite, etc.
  • Carbonates. Carbonic acid salts in the lithosphere are represented by more than 80 minerals. These are magnesite, siderite, dolomite, calcite, etc.
  • Arsenites (antimonites, selenites, bismuthites, telrites and arsenites themselves),
  • Nitrates,
  • Borats,
  • Chromates,
  • Molybdates,
  • Phosphates, i.e. salts of phosphoric acid. There are about 200 minerals of low hardness and density in the class: calcium phosphate, apatites.
  • Tungstates,
  • Silicates, aluminosilicates. These are more than 800 minerals with great rock-forming potential: 80% of the entire earth’s crust. If we classify quartz as silicates, then their share will be more than 90%. Silicates are characterized by a crystal lattice based on a silicon-oxygen tetrahedron: augite, olivine, mica, beryl, etc.
  • Arsenates,
  • Vanadates.

The classification also includes several special supergroups (apatites, laueites, alunites, garnets, mayenites).

According to the international classification, native elements are classified into a separate class. It includes nuggets of gold, platinum, arsenic, mercury, iron, nickel, sulfur and carbon (such as graphite or diamond).

The class of organic minerals also exists and includes some minerals of natural origin (acetates, mellitates, oxalates, etc.). It is necessary to distinguish between biogenic mineral formations and organic minerals. The first include natural bitumen, resins (amber), pearls, copal, ozokerite, and shungite. All these substances do not belong to minerals, since they do not and never have had a crystalline structure. Despite this, they are often mistakenly called organic minerals.

Table of minerals

PROPERTIES OF MINERALS (marked with an asterisk only for crystalline varieties)

Minerals are bodies of natural origin that naturally have a crystalline structure. These also include mercury and some other native liquids that become crystalline when solidified. At the same time, water is not a mineral, but ice is a mineral.

In general, minerals do not include substances of organic origin such as asphalt, bitumen and petroleum, although this is still debated among specialists.

Minerals include glassy substances that do not have a crystal lattice and are in an amorphous state. Outwardly they look like crystals. These are, for example, opals, lechatelierites, and radioactive elements.

Micronutrient supplements used in the food industry and agriculture should not be confused with minerals. Trade uses this concept not entirely correctly, meaning the addition of chemical elements and inorganic compounds.

Talc TM-O Calcium oxide “h” Sodium nitrate

Materials

The properties of minerals are determined by their structure. To describe a substance, its mechanical, optical, magnetic, electrical, radioactive and other properties are determined. Hardness, brittleness, malleability, elasticity, density, and chemical composition are of great importance. Minerals used in jewelry are graded by their luster, color, and hardness. The magnetic and electrical properties of minerals are very important for industry.

It is interesting

Despite the huge number of minerals, most of them consist of only 8 chemical elements: aluminum, iron, potassium, calcium, oxygen, silicon, magnesium, sodium. These elements account for 98% of the mass of the earth’s crust. Most of the earth contains oxygen and silicon.

Very few minerals occur as large ore deposits. Most are impurities in rocks.

Classification of minerals

Currently, more than four thousand minerals are registered. Every year, researchers discover dozens of new ones, and some, on the contrary, are excluded from the list. To understand such a number of substances, mineralogy offers several classification options.

  • By prevalence: rock-forming, accessory (no more than 5% of the total amount of rock), ore (located in ores), rare (single occurrence of crystals).
  • By chemical composition: native, sulfide, halogen-containing, oxides, oxygen-containing salts, minerals of organic origin.
  • By structure. For example, oxides are divided according to their structure into simply oxides and oxides containing hydroxyl groups, and oxygen-containing salts are divided into nitrates, borates, silicates, phosphates, etc.

Organic minerals include:

  • rock-forming substances such as coal, shungite;
  • natural hydrocarbons, such as ozokerite;
  • amber, copal (fossilized resins);
  • salt-like minerals of natural origin (formates, oxalates, acetates, etc.);
  • materials of biogenic origin, which include the mineral aragonite (pearl, coral, mother-of-pearl).

Application

  • In metallurgy for the production of metals and alloys.
  • For the production of a variety of compounds and products: fertilizers, paints, building materials, ceramics and glass, abrasives, refractories and many others.
  • In radio electronics, electrical engineering, optics, chemical industry, food industry, rocketry, agriculture, etc.
  • Ornamental and precious stones, native precious metals are also minerals. They are used in jewelry, for the production of art objects, interior decoration, in high technologies, lasers, microprocessors, etc. Gold, silver, and platinum group metals are an important component of the global financial system.
  • Radioactive elements are in demand in nuclear energy, space technology, medical and scientific research, and military affairs.

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