Mood rings were first seen as an extremely popular fad in the late 1970s, and they resurface regularly! By 1977 the Mood Ring had all but disappeared, but it enjoyed something of a revival in the 90s and up until today.

The idea behind a mood ring is simple: Wear it on your finger and it will reflect the state of your emotions. The ring's stone should be dark blue if you're happy, and it supposedly turns black if you are anxious or stressed. While mood rings cannot reflect your mood with any real scientific accuracy, they actually are indicators of your body's involuntary physical reaction to your emotional state.

How do they work?

Mood rings contain a heat-sensitive liquid crystal encased in quartz. As your body temperature changes, the crystal on the ring changes colour. The colours correspond to your mood at the time (hence, the "mood ring").

The inside of the ring conducts heat from your finger to the liquid crystals in the "stone." The colour green, which signifies "average" on the mood ring colour scale, is calibrated to the surface temperature of a typical person, approximately 82 degrees Fahrenheit (28 degrees Celsius). If your surface temperature varies far enough from the norm, then the liquid crystals in the stone alter enough to cause a change in the colour reflected. And if you take a mood ring off, it will normally change to black unless the ambient temperature is very high.

Take a look at the Mood Ring colours listed below, and what "mood" they represent. The colours are listed according to the change in temperature they represent, with dark blue being the warmest and black the coolest.

Dark blue: Happy, romantic or passionate
Blue: Calm or relaxed
Blue-green: Somewhat relaxed
Green: Normal or average
Amber: A little nervous or anxious
Gray: Very nervous or anxious
Black: Stressed, tense or feeling harried

If you take a moment to think about the moods represented by the colours, you'll see a definite correlation between your body's surface temperature and the colour of the liquid crystal. When you are in a passionate mood, your skin is usually flushed. This is a physical reaction to an emotion, causing the capillaries to move closer to the surface of the skin and release heat. This brings about a slight change in the surface temperature of your body. When you are nervous or stressed, your skin may feel clammy. This physical reaction to your emotional state causes the capillaries to move deeper into your skin, causing the surface temperature to drop.

Who's Responsible?

The Mood Ring was invented by Joshua Reynolds who was a marketing whiz (and an heir to the R.J. Reynolds fortune). Reynolds, a New Yorker who was 33 at the peak of the fad, earned a degree in psychology from Colgate in the mid-60s and went on to invent the ThighMaster. He also claims to be responsible for all those air ionizers as the inventor of the EnergAire.