Touchstones are fun and interactive art. When you press on the back, the pressure causes the liquid crystals inside to change color. You can see a similar effect if you press on the screen of an LCD computer monitor. They also change color depending on your point of view and the available light. Each set includes three touchstones in different colors (pink, orange, and blue). Each Touchstone comes with a display case and is 1 inch in diameter and 1/2 inch tall.