what are the meanings of the colors on a mood ring?

Answer 1

Black: Tense, nervous, harassed, overworked, beaten
Gray: Anxious, nervous, strained
Amber: Nervous, emotions mixed, unsettled
Green: Average reading. Active, not under great stress
Blue-green: Emotionally charged, somewhat relaxed
Blue: Relaxed, at ease, calm
Dark blue: happy, romantic, passion

However, interpretation of the colors differ from maker to maker.

Answer 2

A mood ring contains a substance that changes colour with temperature, there are thermometers that do the same.

I suppose that if it's red (and your temperature is slightly higher) then you are supposed to be excited or happy. If it's blue (and the temperature slight lower) then you're sad. Though I doubt there is any scientific evidence to support this.