Piezo ignition is a type of ignition that is used in portable camping stoves, gas grills and some lighters, and potato guns. It consists of a small, spring-loaded hammer which, when a button is pressed, hits a crystal of PZT or quartz crystal. Quartz is piezoelectric, which means that it creates a voltage when deformed. This sudden forceful deformation produces a high voltage and subsequent electrical discharge, which ignites the gas.
No external electric connection is required, though wires are sometimes used to locate the sparking location away from the crystal itself. Piezo ignition systems can be operated by either a lever, push-button or built into the control knob. Only one electric spark is generated per turn of the knob or press of the button.
Lighters with piezo-electric ignition typically do not work or have great difficulty at high altitude, if the striking mechanism is improperly aligned. They are unsuitable for mountaineering or other high altitude applications. The higher the altitude, the less likely a lighter with piezo-electric ignition is to work. Above 8000 feet lighters with piezo-electric ignition are no longer reliable.