also known as basic violet 14, basic red 9, pararosanaline or CI 42500. Their structure differs from the structure shown above by the absence of the methyl group on the upper ring, otherwise they are quite similar. They are soft, with a hardness of less than 1, about the same as or less than talc. They possess a strong metallic lustre and a green yellow color. They leave dark greenish streaks on paper and when these are moistened with a solvent, the strong magenta colour appears. Chemical structure Fuchsine is an amine salt and has three amine groups, two primary amines and a secondary amine. If one of these is protonated to form ABCNH+, the positive charge is delocalized across the whole symmetrical molecule due to pi cloud electron movement. The positive charge can be thought of as residing on the central carbon atom and all three "wings" becoming identical aromatic rings terminated by a primary amine group. Other resonance structures can be conceived, where the positive charge "moves" from one amine group to the next, or one third of the positive charge resides on each amine group. The ability of fuchsine to be protonated by a stronger acid gives it its basic property. The positive charge is neutralized by the negative charge on the chloride ion. The positive "basic fuchsinium ions" and negative chloride ions stack to form the salt "crystals" depicted above. See also New fuchsine and Acid fuchsine are related dyes Fuchsine is a component in the Schiff test Fuchsine is now often used in the Gram stain procedure in microbiology. Basic Fuchsine is a component in the Lactofuchsin mount References Further reading This provides a detailed account of early experimentation on related chemicals. Triarylmethane dyes Staining dyes Anilines Disinfectants IARC Group 2B carcinogens