Piezoluminescence is a form of luminescence created by pressure upon certain solids. This phenomenon is characterized by recombination processes involving electrons, holes and impurity ion centres. Some piezoelectric crystals give off a certain amount of piezoluminescence when under pressure, as in handheld cigarette lighters when the button is pressed. NaCl, KCl, KBr and polycrystalline chips of LiF (TLD-100) have been found to exhibit piezoluminescent properties. It has also been discovered that ferroelectric polymers exhibit piezoluminescence upon the application of stress.
In the lore of illicit psychadellic substance production, DMT, 5-MeO-DMT, and LSD have been reported to exhibit piezoluminescent qualities. As specifically noted in the book Acid Dreams, it is stated that Augustus Owsley Stansley III, one of the most prolific producers of LSD in the 1960s, observed piezoluminescence in the compound's purest form This piezoluminescence could be related to the general luminescent qualities of both l-tryptophan and l-tyrosine which are precursors to most mind-altering substances, Though there are numerous anecdotal reports on the piezoluminescent properties of psychedelics, valid reported documentation is lacking. This is likely due to both the illegal nature of the compounds—and thus under-researched status, and also from the predictable bias that would occur when observing and ingesting the compound at the same time.