Above: Image © Alkivar, Wikimedia Commons

Can a stone really tell you what your mood is?

Mood rings have been popular since the 1970s and can now be found everywhere from tourist shops, dollar stores and maybe even your local supermarket. But what makes the stone in a mood ring change colour? And does the colour actually relate to your mood?

A mood ring typically has a clear, colourless stone, usually made of quartz or glass. This stone will either sit on top of a thin sheet of liquid crystals, or it may simply be a thin shell filled with liquid crystals. The liquid crystals are thermotropic, which means the orientation of the crystal molecules change with variations in temperature. For example, the crystal molecules may twist or rearrange depending on the temperature.

Did you know? Marvin Wernick invented the mood ring in the 1960s after he saw a doctor taking the temperature of a patient by using a thin strip of thermotropic material.

In addition to being thermotropic, the liquid crystals are also thermochromic, meaning they change colour when the temperature changes. So, when the stone in a mood ring changes colour, it is because the liquid crystals in the stone have changed temperature.

Did you know? In general, the liquid crystals in mood rings are calibrated so that they appear green at 28 °C, which is what mood ring manufacturers consider average skin temperature (medical and dermatological sources cite a much warmer average between 32-34°C).

The range of colours of a mood ring vary from green at the mid-point to blue and violet at warmer temperatures and gray and black at cooler temperatures.

To increase demand for mood rings, they were, and still are, sold with claims that they change colour in relation to the wearer’s emotional state, or mood. Some explanations for this phenomenon are that when you are happy or excited, more blood reaches your skin, causing you to flush. This also warms your skin and, in turn, the stone, causing it to change from green to blue or violet. If you are nervous, you might become clammy as blood moves away from your skin, causing your surface temperature to decrease. The lower temperature of the ring will make it change to a different, darker colour.

However, no scientific relationship between ring colour and your actual mood has been proven and many other things, such as air temperature can also affect a mood ring's colour. So, while mood rings may be pretty and may tell you about your skin temperature, they are probably not the best sign of your emotional state.

Learn More!

wiseGEEK:What are mood rings?

HowStuffWorks:How do mood rings work?

About.com: How do mood rings work?

Article first published January 10, 2011.

Photo Credit: Wikipedia commons

May Cheng

I am a PhD student in the Department of Cellular and Physiological Sciences at UBC, where I am investigating the electrical properties of cardiac potassium channels. When not in the lab, I'm probably cooking up a storm, immersed in a book, or catching a movie.

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