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 occurs next to muscovites and feldspars. Our article will tell you more about the origin, varieties and properties of the biotite mineral. 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 are reading this article, their list will be replenished with a new sample. Every year, geologists discover 50-60 new minerals. But in this article we will talk about only one of them - biotite.
The mineral got its name from the famous French scientist Jean Baptiste Biot. It was he who first engaged in a detailed study of its physical and chemical properties. In 1847 biotite wasofficially registered and added to the general mineralogical list.
The mineral biotite belongs to the class of silicates. Subclass - layered silicates and aluminosilicates. Family - micas. Since biotite can be up to 50% iron oxide, it is also often referred to as iron mica.
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:
- Divalent iron oxide (FeO).
- Trivalent iron oxide (Fe2O3).
- Silicon dioxide (SiO2).
- Potassium oxide (K2O).
- Magnesium oxide (MgO).
- Aluminum oxide (Al2O3).
- Water.
The percentage of each of the listed compounds can vary widely. Other impurities (lithium, manganese, strontium and others) are also present in biotite. Depending on the chemical composition, the color of the mineral can be black, bronze, red, dark green or yellow.
Basic properties of biotite:
- The mineral is flexible and elastic, stratifies into separate leaves.
- Hardness 2 to 3 (Mohs scale).
- Density 2.8 to 3.4 g/cm3.
- Shine glass.
- Monoclinic syngony.
- Transparent in thin plates and opaque in large crystals.
- Melted by candle fire.
- Reacts with sulfuric acid.
- Fades out when exposed to direct sunlight for a long time.
Origin and distribution in nature
The mineral biotite is formed as a result of chemical actions on hornblende and augite. It is found everywhere in nature (as a rule, 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. Widespread in pegmatites, found in many rocks of metamorphic origin. Very often occurs in the earth's crust next to quartz, muscovite, augite and feldspar. The main biotite deposits are 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 is extremely low in iron.
- Rubellan is found exclusively in effusive (lava) rocks. It is distinguished by a rich brick or brown color.
- Bauerite (or "cat's gold") is a bronze-colored mineral.
- Lepidomelane is a mineral with a high content of iron oxides, has a black color.
- Siderophyllite is a mineral with a minimum magnesium content and a high percentage of iron. Color from dark brownto black.
- Glauconite has green crystals that have changed as a result of prolonged contact with sea water. Some scientists deduce glauconite into an independent mineral, not considering it a variety of biotite.
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. The mineral biotite is also used in the construction industry as a heat-insulating material. It is also a component of some fertilizers.
A variety of wooden products are lined with iron mica. Biotite powder is added to paints and enamels to give them shine, as well as to powder and eye shadow. It is sometimes used to make glitter for toys and decorations. Biotite is also used in jewelry, in the production of pendants, bracelets and other designer jewelry. Collectors of stones are hunting for individual, especially large and beautiful specimens.
The mineral is also used for scientific purposes. In particular, in geology, it is used to determine the age and conditions for the formation of certain rocks.
The magical and healing properties of the stone
According to lithotherapists (lithotherapy - treatment with stones), biotite has a number of healing properties. This is the ability to relieve stress, and improve the body's immune system, and strengthen hair and nails. The mineral also normalizes human blood sugar levels.
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 experiences. Red biotite returns fiery passion and love to the life of a married couple, bronze - attracts good luck and financial well-being to the house. Black stones are used to develop intuition.
Many magicians and fortune-tellers use biotite in their rituals to communicate with higher powers. Astrologers assure that this stone suits absolutely all signs of the zodiac. It is especially recommended to be worn by those people who dream of developing their psychic abilities.
