The economic ores of mercury is cinnabar. Cinnabar is a sulphide of mercury usually occurring in massive form. It is bright red to brown in colour. Cinnabar is a heavy ore with a specific gravity of 8 to 8.2 and a hardness of 2 to 2.5.

    It is used in the manufacture of thermometers, scientific instruments, electrical instruments, vapour lamps, dry cell batteries, explosives, chemicals, insecticides and fungicides and in medicine.

    It is a variety of clay. It is used in the manufacture of refractory products.

   It is a variety of clay. It is used for bleaching minerals.

    Apatite is a phosphate of calcium with fluorine or chlorine. It crystallises in the hexagonal system. Crystals are common. It is commonly sea-green or bluish-green in colour and produces a white streak. Its hardness is 5 and the specific gravity is 3.2. Though it resembles beryl, it is easily distinguished by its hardness.

    Apatite is used as a fertiliser.

Zircon