Mood Rings: A Fading Fad Last Christmas, this mood ring sold for $7.50. The Mini Page bought this one in August on sale for $1.50. Like all fads, this gift item is not as popular as it once was. THE Christmas gift item for 1975 was the mood ring ... a kind of thermometer that could put the finger on your emotions for everyone to Bvv* When the ring turns purple, you are happy. When it turns blue, you are peaceful. Green means that you are fun loving. Black means that you are uptight. The ring works because the clear "stone" is treated with a chemical that comes from sheep's wool grease. The chemical responds to changes in the body's temperature. The problem is that the ring reacts to any heat. If you cook over a hot stove, it turns a happy blue. If you play out in the snow, it turns a gloomy black. If someone gave you a mood ring this past Christmas, the chances are that it has already turned splotchy. After two years, it will become completely black.