Destin from Smarter Every Day just polted a cool video on his alt channel: a demonstration of triboluminescence that occurs when a Wint-O-Green Life Saver candy is crushed.
Via Cool Science:
Triboluminescence is not very well understood by scientists, but most think it is similar to the lightning you see during storms or during one of our cool electricity demonstrations, which is actually a type of plasma discharge. Many materials, like the sugar in this experiment, have a very special crystalline structure that causes electrons to be ripped away from the nucleus of their atoms. Since electrons have a negative electrical charge and the protons in the nucleus have a positive charge, separating these charges can create an electrical field strong enough to rip electrons off gas molecules in the air, a process called ionization, and creates a localized plasma. These plasma ions can then slam into other molecules and transfer energy which causes them to emit photons of light. Those are the flashes you observed. Most of the light energy is emitted in the ultraviolet (UV) part of the electromagnetic spectrum, which is just outside the range of light that is visible to humans, but fortunately there is a bit of violet and blue light that we can see.
You should have noticed that the flash of light from the Wint-O-Green Life Saver was significantly brighter, and may have also seemed to last a little longer. This is because wintergreen, the flavoring used in these mints, is a natural fluorescent dye called methyl salicylate. Fluorescent molecules can absorb energy of short wavelengths and emit their own light at a longer wavelength. In our experiment the wintergreen in the mint absorbs a lot of UV energy that we can't see, and emits greenish-blue light which we can see, so it appears much brighter to us.
You can also see it yourself when you bite down on one in a dark room, but please note that Wint-O-Green, while producing a better effect, tastes like biting down on a urinal cake.* Use Pep-O-Mint instead.
*Don't ask how I know.
• LIFE SAVER LIGHTNING (Triboluminescence Slow Motion) (YouTube / Smarter Every Day 2)