The rigid network of carbon atoms, held together by strong covalent bonds, makes diamond very hard. Like silica, it has a very high melting point and does not conduct electricity, ideal for this type of glass processing. Once the punty has been removed then the art of repolishing the glass starts, softening edges and making sure the opening is the correct size to fit our decorative metalwork. This job is definitely suited to those of us with lots of patience and a steady hand!
When a shade is being made in the hot workshop it is connected to the blowing iron by what we call a punty (small pad of hot glass) which acts as a bridge between the glass form and the metal. At the end of of the making process this punty is left on the shade and needs to removed after annealing. This is done in the cold workshop using diamond encrusted cutting and grinding tools.