While the various corundum gems, ruby, sapphire, Oriental topaz, Oriental amethyst, etc., offer a remarkable instance of the many varieties of beautiful coloration observable in a practically identical substance, no single gem-mineral can be said to equal tourmaline in this respect, more especially, however, in the combination of several colors sometimes disposed in bands, at other times in concentric circles in the same crystal. When to this we add its peculiar electric qualities, we may truly say that a fine tourmaline answers our idea of what a talismanic gem or a gem-amulet should be better than any other of the beautiful crystals with which bountiful nature has provided us. These most attractive stones are to be found in widely separated regions on the earth’s surface, as fine examples have been discovered in the State of Minas Geraes, Brazil, and in our own land, in Maine and California especially. Where the color is homogeneous we may have the splendid red or rose-colored variety called rubellite, from its resemblance to the ruby, or the blue tourmaline gem named indicolite. In times of old there was a belief that stones of various kinds would guard against the assaults of evil in the form of witchcraft, disease, and other disagreeable visitations. It was a warlike period in which peace was an unheard-of doctrine, and now that the idea of peace has become one of the ideals of present-day conditions, it is interesting to know that nature has furnished us with a stone at once beautiful, interesting, and illustrating the great fundamental principle of unity and peace. The Peace Stone is formed by the union in one crystal of the green and the red tourmaline, with an intervening band or zone of white, the latter strikingly beautiful effect being due to the combination at this point of the red coloring matter, manganese, and the iron constituent, the source of the green hue; these two materials, by their union, neutralize each other, furnishing the transparent, colorless vein or zone. A slightly different combination of colors appears in a fine crystal, found some years ago at Mount Mica, Oxford County, Maine; this even offers a kind of “triple alliance,” as it shows blue in its lower half, passing through white and pink to a grass-green at the upper end.[103] These three hues combined in one body, in indissoluble union in spite of the differences of quality and color, yet represent one principle. This action of manganese in neutralizing the iron is well known to glass-makers; otherwise white glass could not be made. It would all be greenish in tint were it not for the use of oxide of manganese, or “glass-maker’s soap,” as it is termed, which neutralizes the production of a green tint by the iron and makes the white hue.