Purple (Gr. ; Lat. purpura), a color produced by the union of red and blue, and of various shades as one or the other of these predominates. The ancients esteemed it more highly than any other color, sometimes making it a distinctive badge of royalty, and again appropriating it to religious uses, as the decorations of the temple and of the garments of the priests. In the Old Testament it is frequently referred to in Exodus and other books. But it is supposed by some that the purple of the Israelites was a scarlet, or even that the term was used generally for any color in which red predominated. Tyrian purple, the purple of the Greeks and Romans, was obtained from the murex, a genus of gasteropod mollusks found in the Mediterranean. (See Murex.) The use of this color passed away with the decline of the Roman empire, and a simple purple color, that is, one not made by using two separate dyes, was not known until a Florentine, Orchillini, discovered the dyeing properties of the lichen called orchilla weed.
Other lichens growing in different parts of the world now furnish the dye known as orchil or archil. (See Archil.) Shades of purple are abundantly obtained from coal-tar colors. (See Aniline, Dyeing, and Mauve.) The compounds called "purpurates," especially the purpurate of ammonia, called by Liebig and Wöhler murexide, from its resemblance to the Tyrian purple, present beautiful shades of purple. (See Purpurates).