How Do Mood Rings Work?

Thermochromic Liquid Crystals and Mood Rings

Modern mood rings are acrylic gems coated on the back with a layer of thermochromic liquid crystals.
Modern mood rings are acrylic gems coated on the back with a layer of thermochromic liquid crystals. taryn/Getty Images

The mood ring was invented by Joshua Reynolds. Mood rings enjoyed fad popularity in the 1970s and are still around today. The stone of the ring changes color, supposedly according to the mood or emotional state of the wearer.

The 'stone' of a mood ring is really a hollow quartz or glass shell containing thermotropic liquid crystals. Modern mood jewelry is usually made from a flat strip of liquid crystals with a protective coating.

The crystals respond to changes in temperature by twisting. The twisting changes their molecular structure, which alters the wavelengths of light that are absorbed or reflected. 'Wavelengths of light' is another way of saying 'color', so when the temperature of the liquid crystals changes, so does their color.

Do Mood Rings Work?

Mood rings can't tell your emotional state with any degree of accuracy, but the crystals are calibrated to have a pleasing blue or green color at the average person's normal resting peripheral temperature of 82 F (28 C). As peripheral body temperature increases, which it does in response to passion and happiness, the crystals twist to reflect blue. When you are excited or stressed, blood flow is directed away from the skin and more toward the internal organs, cooling the fingers, causing the crystals to twist the other direction, to reflect more yellow. In cold weather, or if the ring was damaged, the stone would be dark gray or black and unresponsive.

What the Mood Ring Colors Mean

The top of the list is the warmest temperature, at violet, moving to the coolest temperature, at black.

  • violet blue - happy, romantic
  • blue - calm, relaxed
  • green - average, not much going on with you
  • yellow/amber - tense, excited
  • brown/gray - nervous, anxious
  • black - cold temperature or damaged ring