A mood ring is a ring that changes color according to the body temperature of the person who's wearing it. The color of the ring is supposed to represent a corresponding emotion that the wearer is feeling.
The mood ring was created in 1975 by Josh Reynolds and Maris Ambats by bonding liquid crystals with quartz stones and then set into the rings.
Mood rings are basically wearable liquid crystal thermometers. Changes of temperature cause the crystals to change different wavelengths of light, thus changing the color of the stone. The initial stone color is set for the human skin temperature, roughly 37°C, and has a neutral color. When body temperature changes, so does the color of the ring.
There has never been scientific evidence that body temperature actually reflects a person's mood, but it didn't take away from the novelty of these items because these were a huge fad in the 90s.
Emotions and Colors
Black-Fear, Nothing, Angst, Serious, Overworked, Stormy, Depressed, Intense
Yellow-Anxious, Cool, Cautious, Distracted, Mellow, So-So
Orange-Stressed, Nervous, Mixed, Confused, Upset, Challenged, Indignant
Green-Peridot-Mixed Emotions, Restless, Irritated, Distressed, Worried, Hopeful
Green-Light Green-Normal, Alert, No Great Stress, Sensitive, Jealous, Envious, Guarded
Blue-Green-Upbeat, Pleased, Somewhat Relaxed, Motivated, Flirtatious
Blue-Normal, Optimistic, Accepting, Calm, Peaceful, Pleasant
Indigo-Darker Blue=Deeply Relaxed, Happy, Lovestruck, Bliss, Giving
Violet-Burgandy-Love, Romance, Amorous, Heat, Mischievous, Moody, Dreamer, Sensual
Pink-Very Happy, Warm, Affectionate, Loving, Infatuated, Curious
Pictures
via http://adrianhickman.wordpress.com
Video
Featured image via badgespot.com