Vermiculite

    Phlogopite is an yellowish brown to brownish red mica. Its hardness varies from 2.5 to 3 and the specific gravity ranges from 2.7 to  2.9.

    Phlogopite occurs in crystalline limestone and dolomite.

    Muscovite or potash mica is the most common and light coloured variety of mica. Its hardness varies from 2 to 2.2 and the specific gravity ranges from 2.8 to 3.

    Muscovite is chiefly used as an insulator in the manufacture of electrical equipment. India has rich deposits of muscovite  occurring in Andhra Pradesh, Bihar and Rajasthan.