Polarised light micrograph of a mixture of the hydrated forms of manganese and ferrous sulphates with nickel nitrate. Ferrous sulphate is used to treat and prevent iron deficiency (anaemia) and for industrial applications. Manganese sulphate is used to treat osteoporosis, anemia and premenstrual syndrome. Nickel nitrate is used for nickel plating. Magnification: x70 when printed at 10cm wide.