The invention relates to a process and apparatus for forming a particulate composition, especially a particle glass composition, through the use of shock waves. A nozzle element is utilized having inlets for introduction of cold and heated gas and a delivery tube for introducing molten material. Through the introduction of the cold and heated gases, droplets are formed from a molten stream, a cone-shaped standing shock wave is formed, and shock waves are formed via a modified Hartmann-Sprenger chamber, the shock waves impinging on the droplet stream to break up the larger droplets.