Mica is considered to be a gift of nature. It has exceptional physical properties that are useful in numerous industrial applications. It can be found in various parts of the world, primarily in locations where Paleozoic rocks are present. Accessible deposits can be mainly found in parts of India, and also on the American continent, Russia and southern Africa. The chemical composition of this is such that it is placed in the aluminum silicate category. In the first few stages of the electric insulation industry, uniform quality of mica were available in large number. These could be directly used after doing the task of splitting. As the easily available supplies started to deplete, a system was developed so that the smaller ones could be used. With the help of this setup, a continuous foil could be obtained by combining the mica splittings. A substrate like cotton and paper were used for this in addition to using asphalt or shellac. With the ever-increasing demand for mica paper and various other mica-based insulation products, a completely new technique came into the picture. The time was around the 40s and 50s. With the help if this technique, continuous sheets of pure mica could be produced, comprising of tiny platelets that allowed them to retain their basic characteristics even when the size was greatly reduced.
There are mainly 3 main types of mica that are discussed below:
Muscovite
It is a phyllosilicate mineral that is taken from aluminum. It is a highly flexible and elastic mineral and can range from being transparent to translucent depending on various factors. It also has a silky or pearl gloss. It has got the ideal cleavage that allows it to be made into finer sheets (thin) or flakes. Muscovite is also known as ‘white mica.’ Talking about its application, it is used as filler in gypsum wallboard joint cement. It is also used as an ingredient in specific lubricants in various railway wagon axes.
Phlogopite
Phlogopite is also popularly known as Magnesium Mica. It is usually light to dark brown in color and its dark brown variant is much similar to the likes of Biotite. Phlogopite is basically comprised of magnesium, iron, and aluminum silicate. When a light source is viewed by using a thin crystal, an asterism can be seen. This is caused mainly because of the iron inclusions. As for its application, it is used as a non-stick surface coating on asphalt. It can also be used as filler in the protection of the chemical plants.
Biotite
It is a highly common phyllosilicate mineral present in the mica group. The high percentage of iron ions imparts it a dark hue. It is also sometimes referred to as “iron mica” since it is more iron-rich than phlogopite. It is also known by the name “black mica.” As for the industrial applications of biotite is concerned, it can be used as an insulating material in the electronics sector. They can also be used as mica glass for wood stoves.
