The molten crystal is picked up by the master glassmaker in a melting furnace, using a metal rod. The viscous mass of material is shaped with the help of tools, made of wood or metal, and then blown. The crystal is worked at a temperature of between 2,000°F and 2,300°F (1,100°C and 1,200°C). The history of glass stretches back more than 100,000 years before Christ, with the use by humans of obsidian, a natural volcanic glass, for carving tools and weapons. Blown glass appeared among the Phoenicians in the 3rd century BC. The technique of blown-moulded decoration was perfected by René Lalique in the early 20th century.