Malachite green colored cation. The oxalate salt is also marketed. The anions have no effect on the color. The intense green color of the cation results from a strong absorption band at 621 nm (extinction coefficient of ). Malachite green is prepared by the condensation of benzaldehyde and dimethylaniline to give leuco malachite green (LMG): Second, this colorless leuco compound, a relative of triphenylmethane, is oxidized to the cation that is MG: A typical oxidizing agent is manganese dioxide. Hydrolysis of MG gives an alcohol: This alcohol is important because it, not MG, traverses cell membranes. Once inside the cell, it is
Mineral the various species, which were determined by the mineral's geological environment when formed. Changes in the temperature, pressure, or bulk composition of a rock mass cause changes in its minerals. Within a mineral species there may be variation in physical properties or minor amounts of impurities that are recognized by mineralogists or wider society as a mineral "variety", for example amethyst, a purple variety of the mineral species quartz. Minerals can be described by their various physical properties, which are related to their chemical structure and composition. Common distinguishing characteristics include crystal structure and habit, hardness, lustre, diaphaneity, colour, streak,