Mica

Mica is a group of sheets, (that glitter). Which has almost perfect cleavage, that is it can be separated into these sheets.  These sheets are in Polygonal and
Hexagonal crystals and are the primary make up of Mica.  Though,
Fluorite is a mineral which is a part of mica, as is also the following minerals; Muscovite( potassium mica), Lepidolite, Phlogopite (magnesium mica) and vermiculite (a hydrated mica).
Mica's are common in the formation of igneous (which is a rock that has formed under intense heat from inside the earth from magma and lava, and metamorphic rocks, which is also igenous but has come from already existing igenous rocks.  They look different to each other, so two rocks are never the same.

Mica is produced all over the world. Countries including are Russia,(which produced mica first), China, the United States, Brazil, Africa and South America.
To this date though, India is the largest supplier muscovite mica, with Brazil following.
Australia too mines Mica, the Williamstown deposit, near Adelaide S.A, is the largest in Australia.  It is mined by the company Unimin Ltd, and produces approximately 1000 tonnes of muscovite each year. Smaller amounts have been found  in the district of Olvary South Australia.

How is Mica Mined?

The Room and Pillar method is used in the mining of mica. This is where mica is taken from the mine which is called crude mica. It needs a little cleaning to remove some dirt as well as any flawed  portions.They are split away with a sickel tool.
There are also 4 ways to crush mica, and they are as follows;

The Jaw crusher , this is the most used machine used to crush mica.  The smaller jaw crusher is 1t/p and the larger jaw crusher is 300-800 tons/p. The jaw crusher has a motor-driven belt and pulley system through the shaft to move the Jaw Crusher up and down before and after, the materials are then crushed, split up or broken down.
The hammer crusher , a machine used in the crushing of mica. It is quite fast and can crush mica into less than 15 mm in size.
Ball mill is also another most common mica mill machine. The final size is 0.074-0.4mm, and the strength of ball mill is 1-30 ton/p.
Raymond mill is another of the crusher mills used in mica processing plant. It can crush so finely up to 0.044mm. The capacity is 1-3t/p.

How Mica is Processed

Mica in its natural form resembles crystals, rough and in all odd shapes and sizes. There are imperfections in size and thickness. There is a lengthy process of sorting and cutting to get from the crude state to commercial quality.  The waste, (scrap mica), as part of the process, results as scrap mica to crude of approximately 60 to 90 %.  With some of the scrap mica can be used and ground down to create mica powder. 

Mica is processed by requiring a pair of hands, sharp eyes and a knife, as there is no machines to process Mica.
The process involves cleaning of the crystals and of all impurities. Done by splitting the  mica into sheets which can be used by the sickle tool. This sharp knife is then used to remove all large flaws, cracks holes and imperfections. Trying to do this with minimal wastage of the mica sheet. The trimming of mica takes a steady skilled hand so that all cracks and imperfections are taken from the edge of the sheets while keeping the favoured area of usable sheet. Then finally polygonal shapes of mica are sorted into different sizes of qualities before they are sent out to the market world.

What is mica used for?

Mica has such a wide variety of uses, ranging from, electrical heating appliances, electrical control, lighting equipment, radar and television.
Even mechanical uses, such as breathing oxygen apparatus, guided missiles and diaphragms for hearing aids.

Electrical heating appliances like steam and waffle irons, portable clothes dryers, rice cookers and water heaters.
Some electrical control uses, electrical regulators, remote control panels and industrial starter motors.
There are several electrical items, including neon lights, dimmer switches and flashers.
Industrial electric heating appliances like thermostats and heating elements for stoves contain mica.
Many miscellaneous items also include spark plugs, covers for fuse plugs and insulators.
Mica powder is also useful as a filling substitute for rubber tyres.

As mica is heat resistant and very flexible it was was an alternative to glass many years ago, being used for lanterns and windows and wood stoves. So there are no breakages under pressure, vibrations or temperatures.

Mica has reflective substances which glitter.  So is a great ingredient in make up.  Items include eye liners, foundations, body glitters, mascara, nail polish and moisture lotions, and the list goes on.