Malachite Green (MG)

Malachite green is an organic compound that is used as a dyestuff and has emerged as a controversial agent in aquaculture. Malachite green is traditionally used as a dye for materials such as silk, leather, and paper. Although called malachite green, the compound is not related to the mineral malachite — the name just comes from the similarity of color. Malachite green is classified in the dyestuff industry as a triarylmethane dye. Formally, Malachite green refers to the chloride salt [C6H5C(C6H4N(CH3)2)2]Cl, although the term Malachite green is used loosely and often just refers to the colored cation. The oxalate salt is also marketed. The chloride and oxalate anions have no effect on the color. Malachite green is traditionally used as a dye. Millions of kilograms of MG and related triarylmethane dyes are produced annually for this purpose.