Mica is a group of a complex aluminosilicate minerals having a sheet or plate like structure with different chemcial compositions and physical properties. It is mined in the form of "blocks" or rocks, which are then rifted to arrive at thin flexible natural mica splittings. Mica is a complex hydrous silicate of aluminium, containing potassium, magnesium, iron, sodium fluorine and/or lithium and also traces of several other elements. It is stable and completely inert to the action of water, acids (except hydro-fluoric and concentrated sulphuric) alkalies, conventional solvents, oils and is virtually unaffected by atmospheric action. It is transparent, optically flat, easily splittable into thin films along its cleavage, colourless in thin sheets, resilient and incompressible.Mica has a high dielectric strength to prevent current from flowing across it at moderate voltages.