Heraeus chemist Richard Küch first began fusing quartz rock crystal in an hydrogen/oxygen (H₂/0₂) flame more than 100 years ago. Heraeus has been producing quartz glass on an industrial scale with this process ever since. The basic process consists of trickling high purity silica sand at a controlled rate into a high temperature H₂/0₂ flame. There it melts and collects on a bait rod that is slowly withdrawn from the flame thus forming a slid round ingot. This ingot can then be shaped into any desired dimension.