Here’s a description from original product packaging:
This unique plastic disc is filled with fascinating liquid crystals. Just a touch on the back causes liquid to flow into a spectacular show of changing hues and patterns.
These fun toys are made of plastic and filled with thermotropic liquid crystal; the same material found in mood rings. The crystals respond to changes in temperature. The image created would simulate the iridescent colors seen in a puddle of oil:
This 1970's toy was a thin, octagonal hand-held kinetic toy with a clear plastic window over color-changing goo. It looked a little like a drink coaster, and measured about 3-inches across.
The octagon plastic disc filled was with liquid crystals that you would touch for different patterns. Just a touch on the back caused the encased liquid to flow into a spectacular show of changing hues and patterns.