A hollow glass prism gives no spectrum because it has no medium inside. It is hollow from the inside, so white light can not split in a vacuum because, in a vacuum, all colours of light travel at the same speed; hence they do not split, and no spectrum is observed. Score the tube once with a triangular file. Turn the scratch away from your body, placing your thumbs opposite the scratch. Push your thumbs away from you. The glass tube should break cleanly at the scratch. Glass pipes are rarely made of Soft Glass because of the application's constant heating and cooling requirements. As a hard-to-grind material, waste glass was often ground into powder by a ball mill to be used as a supplementary cementitious material in concrete. Price. Artisan glass beads take a great deal of time to create. The artisan has usually studied glass for years before they sell their work, often taking many classes to perfect their skill. There is a great deal of time invested in each bead and the cost of equipment and raw materials. The term "frit" refers to granular crushed glass. Soft glass frits have been available to glass artists for a long time in many colours and several different mesh sizes. Glass melting requires raw materials of two kinds: different types of sand and recycled glass. These raw materials are mixed and charged in a furnace where there are melted at around 1500°C to form molten glass. If you are looking for high quality, high purity and cost-effective zinc sulfide, or if you require the latest price of zinc sulfide, please feel free to email contact mis-asia.