In 1903 Auer von Welsbach won another patent for a fire striker ("flint") composition named ferrocerium. It takes its name from its two primary components: iron (from ), and the rare-earth element cerium. It is also known in Europe as "Auermetall" after its inventor. Three different Auermetalls were developed: the first was iron and cerium, the second also included lanthanum to produce brighter sparks, and the third added other heavy metals. In Auer von Welsbach's first alloy, 30% iron (ferrum) was added to purified cerium, hence the name "ferro-cerium".
Welsbach's flints consisted of pyrophoric alloys, 70% cerium and 30% iron, which when scratched or struck would give off sparks. This system remains in wide use in cigarette lighters today. In 1907 he formed Treibacher Chemische Werke GesmbH to build and market the devices.