Biotite (another name is iron mica) is a fairly soft and elastic mineral that can be easily machined. In the earth's crust, it often lies near muscovites and feldspars. In more detail about the origin, varieties and properties of the biotite mineral our article will tell. From it you will also learn where this stone is used and what healing qualities it has.
Biotite: mineral class and origin of the name
Modern science has about 4 thousand different minerals in the world. It is possible that while you read this article, their list will replenish with a new sample. Geologists discover 50-60 new minerals annually. But in this article we will tell only about one of them - biotite.
The mineral got its name from the famous French scientist Jean Baptiste Bio. It was he who first engaged in a detailed study of his physical and chemical properties. In 1847, biotite was officially registered and added to the general mineralogical list.
Mineral biotite belongs to the class of silicates. Subclass - layered silicates and aluminosilicates. The family is mica. Since biotite can be composed of iron oxides by almost 50%, it is also often called iron mica.
The chemical composition and basic properties of the mineral
Biotite is very heterogeneous in its chemical composition. Most often it consists of the following substances and compounds:
- Ferrous oxide (FeO).
- Ferric oxide of iron (Fe 2 O 3 ).
- Silica (SiO 2 ).
- Potassium oxide (K 2 O).
- Magnesium Oxide (MgO).
- Alumina (Al 2 O 3 ).
- Water.
The percentage of each of these compounds can vary within wide limits. Other impurities (lithium, manganese, strontium and others) are also present in biotite. Depending on the chemical composition, the color of the mineral may be black, bronze, red, dark green or yellow.
The main properties of biotite:
- The mineral is flexible and elastic, exfoliates into separate leaves.
- Hardness from 2 to 3 (on the Mohs scale).
- Density from 2.8 to 3.4 g / cm 3 .
- Glitter glass.
- Monoclinic syngony.
- Transparent in thin plates and opaque in large crystals.
- Melts from the fire of a candle.
- Reacts with sulfuric acid.
- Under prolonged exposure to direct sunlight, it burns out.
Origin and distribution in nature
Mineral biotite is formed as a result of chemical effects on hornblende and augites. It is found everywhere in nature (usually in the form of lamellar or columnar forms) and makes up about 2.5% of the mass of the earth's crust.
Biotite is a rock-forming mineral for granites, trachytes, granodiorites. Widely distributed in pegmatites, it is found in many rocks of metamorphic origin. Very often lies in the earth's crust next to quartz, muscovite, augite and feldspar. The main biotite deposits are located in Germany, Italy, Russia, Norway and Canada. Very beautiful stones are also mined in Tanzania, Greenland and Alaska.
Main varieties
Depending on the chemical composition and content of certain impurities, geologists distinguish several varieties of biotite. We list the most common of them:
- Meroxen has an extremely low iron content.
- Rubellan is found exclusively in effusive (lava) rocks. It stands out with a rich brick or brown color.
- Bauerite (or “cat gold”) is a bronze colored mineral.
- Lepidomelan is a mineral with a high content of iron oxides, has a black color.
- Siderophyllite is a mineral with a minimal magnesium content and a high percentage of iron. Color from dark brown to black.
- Glauconite has green crystals, which have changed as a result of prolonged contact with sea water. Some scientists bring glauconite into an independent mineral, not counting it as a kind of biotite.
The practical application of biotite
One of the varieties of the mineral (phlogopite), due to its unique insulating properties and resistance to high temperatures, is widely used in radio engineering and electronics. Mineral biotite is also used in the construction industry as a thermal insulation material. It is also a component of some fertilizers.
Iron mica is faced with a variety of wooden products. Biotite powder is added to paints and enamels to give them shine, as well as to powder and eye shadow. Sometimes sparkles are made from it for toys and decorations. Biotite is also used in jewelry, in the production of pendants, bracelets and other designer jewelry. Collectors of stones hunt for individual, especially large and beautiful specimens.
The mineral is also used for scientific purposes. In particular, in geology with its help determine the age and conditions of formation of certain rocks.
Magical and healing properties of stone
According to lithotherapists (lithotherapy - stone treatment), biotite has a number of healing properties. This is the ability to relieve stress, and improving the body's immune system, and strengthening hair and nails. The mineral also normalizes human blood sugar.
The magical properties of biotite are largely determined by the color of a particular mineral. So, a green stone helps a person get rid of internal conflicts and feelings. Red biotite brings fiery passion and love to life of a married couple, bronze - attracts luck and financial well-being to the house. Black stones are used to develop intuition.
Many magicians and fortunetellers use biotite in their rituals to communicate with higher powers. Astrologers claim that this stone is suitable for absolutely all signs of the zodiac. It is especially recommended to be worn by those people who dream of developing their psychic abilities.