The recipe for making glass has changed little for several thousands of years: sand, alkali ashes, and lime from crushed stones are melted together to give a strong, yet fragile material. This molten material can then be manipulated by the glassmaker in a number of ways.This Italian tazza, dating from 1590-1600, was free blown. This is where air is blown down a metal tube that has a blob of glass at its end creating a bubble. This bubble of glass would then have been then shaped using a variety of tools to create the desired form.The white lines of decoration are known as latticino, the word is derived from the Italian latte, meaning milk. The lines are threads of white glass running through the body of clear glass.