1) What is glass?
Obsidian is a naturally occurring volcanic glass, which is generally found in darker colors such as black and red. It is very rich in silica, the main element used for glass production.
How it's made:
Main element : Silica (SiO2, Silicon dioxide) is the fundamental element of every type of glass. Most glass recipes contain between 40 and 80% silica, and its main sources are from sand, quartz and silex.
Melters: Borax (B2O3, Sodium tetraborate), Sodium Carbonate (Na2CO3) and potash (K2CO3, potassium carbonate). These substances have a melting effect which produces what we call pâte de verre, literally glass paste.
Stabilizers: Lime (CaCo3, calcium carbonate), natural magnesium carbonate (MgCO3), minium (Pb3O4, lead oxide) are what allows the glass to become resistant against chemicals and humidity.
2) How is it colored?
Glass coloration is made with metal oxides being mixed in with heated glass paste. There is a variety of oxides, each of them has specific colors, such as green-blue for chrome oxides, purple-brown for manganese.
3) What are the most useful tools for a glass artist?
The cane is obviously vital for the glass artist, but the metal scissors are also very important to give shapes and cut glass. Moreover, a wet newsprint paper is used to polish and finish the surface.