A gaseous fuel-oxygen burner is described herein. One device includes a flame zone in which combustion of gaseous fuel and oxygen occurs to form a flame, a coaxial gaseous fuel jet configured to provide the flame zone with gaseous fuel, and a coaxial oxygen jet configured to provide the flame zone with oxygen, wherein the coaxial gaseous fuel jet and the coaxial oxygen jet are separate such that the gaseous fuel from the coaxial gaseous fuel jet and the oxygen from the coaxial oxygen jet do not mix before entering the flame zone.