Is rubbing flint and steel together considered triboluminescence? When you rub flint and steel together the friction creates fire so is it considered triboluminescent or incandescent light?
 A: The triboluminescence effect is a mechanical effect caused by breaking or separating a material. The light is given off as electrons on the newly formed surfaces settle.
The sparks resulting from striking flint on steel, counter-intuitively, is a chemical reaction. It is the steel that sparks in this reaction. It turns out that oxidizing iron gives off heat, and when the piece of metal is small enough, the surface-area-to-volume ratio is so high that this is enough heat to make the fragment glow white-hot.
So “flint” (meaning steel) glows because it is very hot, because of the exothermic chemical reaction of iron with oxygen. So it would seem to be unrelated to triboluminescence, a mechanical effect that doesn’t particularly care about the chemical makeup of the surfaces on which it occurs (good question though, I didn’t know that until looking it up).
A: No. In the case of flint rubbing on steel, there's a chemical reaction taking place between air, iron, and rare earth oxides in the flint which causes the iron to burn, which is the "spark" you see.
