Triboluminescence is a flash of light produced when a material is subjected to friction, impact or breakage. The phenomenon is also known as fractoluminescence and mechanoluminescence. Triboluminescence is common in minerals. About 50% of crystalline materials are thought to exhibit the property. It is also observed in many noncrystalline materials [1].

How to Demonstrate Triboluminescence

**** Safety glasses recommended ****

A very easy way to observe triboluminescence is to get two milky quartz pebbles that are large enough to easily hold and rub together with a bit of force. Take them into a darkened room and stand in the dark for a few minutes to allow your eyes to adjust to the darkness. You don’t need total darkness but the less light the better.

Hold one piece of quartz in your left hand and the other piece in your right hand. Firmly press an edge of one piece of quartz against the other and while holding firm pressure, quickly drag it across the surface in a motion similar to what you would use to strike a large match. Don’t be wimpy. Hold firm pressure while you quickly drag one pebble across the surface of the other. If you do this properly and if you have pieces of quartz that are triboluminescent, you will see a brief flash of light that penetrates deeply into the translucent quartz.

Experiment with different speeds, different amounts of pressure, and directions of drag to maximize the flash of light. Some specimens will also produce small amounts of light if you bang them together or rub them against one another. You can also experiment with different minerals to see if they are triboluminescent. You will probably find many minerals that exhibit the property.