Biotite: what are its properties and how can a stone be used?

Biotite is a mineral that is also known as dress and iron mica. It represents translucent plates or less transparent crystals. This mineral can be seen in various shades: bronze, yellow, dark green, red-brown and black.

The study of this mineral began in the 19th century. Jean-Baptiste Bio, a military specialist, academician, physicist and mathematician, in whose honor the stone was named, was actively engaged in its research and description. Mineralog Johann Hausmann continued the work of the French scientist and delimited a separate group of biotite substances. Only at the beginning of the 21st century could knowledge of stone be called relatively complete.

Biotite is often found in nature, in total in the earth's crust its presence is about 2-3%, which is a considerable indicator. Most often, the word biotite means brown or black shiny mica, but also the concept of biotite can replace a group of ferrodominant members of the phlogopite - annite series.

In nature, you can see very large stones, collectors are eager to purchase them. This is not surprising, because even among these seemingly inconspicuous stones, you can find large plates, which in their ability to reflect the image resemble a mirror.

Note that not so long ago there was an opinion that Biotite cannot be ranked as a mineral. Scientists decided that this is a solid solution of various natural substances.But for now, we will focus on the traditional point of view, which implies the status of a mineral in biotite.

There are several types of mineral by origin, Depending on this parameter, biotites are divided into the following groups:

• granitecontained in magma rocks;
• metamorphic - found in shales or gneisses;
• pegmatite - present in basalt sediments.

The crystals of the mineral have different colors, which are determined by the impurities of the rock. Black and brown specimens are distinguished, sometimes stones with a green or reddish tint occur in nature. Crystals of a mineral are columnar or tabular in shape. Leaflets can be characterized as elastic, this mineral is more elastic than many others. Light can penetrate through biotite plates.

The fusibility of the stone varies for different species. For example, Miass biotite melts from 11.5 thousand degrees. The chemical composition of the stone also varies and can be delineated only within certain limits. As a rule, the stone structure implies the following components: potassium oxide occupies from 4.5 to 8.5%, magnesium oxide from 0.3 to 28%, ferrous oxide - from 2.8 to 27.5%, aluminum oxide - from 9.5 to 31.5%, silica from 33 to 45%, water from 6 to 11.5%.

Oxides of lithium, sodium, barium, titanium, manganese, strontium, cesium, etc. are also found as impurities in biotite. They can give the stone a small radioactive background. To decompose a mineral, it is necessary to act on it with sulfuric acid concentrate.

As we have already said, the color of the stone biotite varies depending on the impurities. We list the main types of biotite, depending on this parameter.

• Lepidomelans - have a saturated black color.
• Meroxenes - due to the low concentration of impurities, iron is transparent.
• Rubellans - they are distinguished by brown or terracotta shades.
• Sideophyllites - they lack magnesium, but there are many impurities of iron. Therefore, the color of these unusual stones is greenish.

In deposits, it detects biotite, which has various forms. It is found in the form of lamellar, scaly and columnar formations. Often this stone lies in the rocks next to feldspars, granites, muscovites and andalusites. Biotite is so widespread that among mica, it is second only to muscovite. Therefore, it makes sense to note only the most famous deposits.

In the Ilmen mountains, stone comes across as a minor mineral in pegmatite veins. There it lies in the form of plates up to half a meter in diameter or in crystalline form. In the Borschovka ridge, biotite is observed on the Slyudyanka River. Large plates of biotite are found in Greenland, as well as in Scandinavia - even seven-meter plates are found on these lands, which is a large size. In Germany, this mineral is found in granites; in the Granulite Mountains, biotite pegmatites are often found. Well-known mineral sources are located in the areas of Burgmau and the Turengen Forest.

The stone is characterized by glass shine, its specific gravity is 2.8-3.4 g / cm3. For certain species, the presence of a trait is characteristic. It has perfect cleavage, can be decomposed into leaves. Interference coloring in red, blue, green tones. The hardness of the stone is not very high - it cannot scratch the glass.

If erosion occurs, then biotite takes the form of a placer with all its signs, easily separated with the finest silty material in stagnant waters. The mineral biotite-vermiculite appears. After a certain time, the stones obtained get a golden color due to the sparkles, which, when washed, precipitate.

Lithotherapists note the ability of the mineral to treat nervous disorders, eliminate anxiety, stabilize the pulse and establish a healthy sleep in people who suffer from insomnia. Biotite improves the protective functions of the body, and also stabilizes the endocrine system, helps normalize blood sugar. Among mineral connoisseurs, biotite is known as a stone with some magical properties. They may vary depending on the colors in which biotite is painted.

• To find material prosperity, you need to put pieces of mineral in bronze tones in your wallet.
• In order for peace and tranquility to reign in the soul, experts advise carrying green specimens with them.
• Pink-red stones guard the family hearth. They also help to find happiness in personal relationships.

The practical application of biotite includes various areas.

• Engineering. Since biotite, like all other micas, perfectly isolates, it is actively used in electronics, namely, in the creation of devices necessary in shipbuilding and aircraft building. The plates found application in the development of navigation devices. For the production of small equipment, the mineral is also widely used, for example, in the production of microwave ovens.
• Construction. Biotite is part of vermiculite, so it is used as a filler to create soundproofing and thermal insulation in homes. Its decorative properties are also appreciated - it can be used for cladding wood panels, giving them a more beautiful and expensive look. Also, mineral powder is sometimes added to the tile.
• Gardening. Due to the good ion exchange of the stone, it is saturated with liquid fertilizers with trace elements useful for plants.
• Repairs. In the production of various paints and enamels, biotite is added to obtain heat-resistant coating compositions.
• Cosmetic industry. Small pearlescent particles are obtained from the stone, which are added to powders and other decorative cosmetics.
• In jewelry. Using the cabochon method, craftsmen get pebbles decorating various jewelry: rings, earrings, pendants, pendants, etc. A placer of biotite in the composition of feldspar gives a stone called aventurine. An interesting fact is that a rare effect for emeralds - a six-pointed star is obtained if particles of biotite fall into the crystal.
• In geology. Scientists use the isotopic geochronological method to determine the age of mountain fragments from biotite.
• Decor. The mineral can be used to create sequins for toys and theatrical scenery.

Despite the fact that the scope of the mineral is already quite wide already, it is still being closely studied and new promising directions are being found. So, biotite is a very common mineral that is found in different parts of the planet. It serves as a material for the creation of technology, including large units in mechanical engineering, construction, in the cosmetics industry and other fields.

In the next video, you can take a look at biotite in motion.