379.942 393.969 407.996 Methyl violets are mixtures of tetramethyl, pentamethyl and hexamethyl pararosanilins, the last also being known as crystal violet . Due to this, the particular shade differs depending on the amount of each present. The more methylated the homologues present are, the darker blue the sample will be.
Methyl violets are metachromatic, and are often used to demonstrate amyloid.
Their commonest use, however, is in Gram's stain for the demonstration and primary classification of bacteria. The name gentian violet is given to many of the dyes in this general group, and can not be relied upon to give any consistency in identification. It is preferable to avoid the name altogether. Reference Conn's Biological Stains R. D. Lillie.