Glass of a yellow- brownish colour; translucid, in which copper metal micro- crystals are dispersed to reflect a gold colour; formed by devetrification (separa- tion from the molten mass during the cooling step). It is prepared by melting the mixture of transparent colourless glass with the ad- dition of cuprous oxide and iron and lead oxides. Mel- ting takes place in a reducing chamber and the molten mass should be cooled very very slowly.
Traditionally, to obtain the best quality, once the mass is molten, the oven is switched off and left to cool on its own for several days. Once room temperature is reached the crucible is smashed and the avventurina is found under a layer of colourless oxidized glass. This glass found its highest application in Murano in the mid-nineteenth centu- ry, first at the furnaces of Pietro Bigaglia and then at Salviati & C., where it was melted once again and blown to obtain extremely rich and elegant items, often made for the royal families of the day.
In the twentieth century avventurina was used by only a small number of glass-works as it was very difficult to obtain. Special mention should be made here of Barovier & Toso’s and Aureliano Toso’s who, on designs by the painter Dino Martens, executed a series of vases with this material decorated with applied multicoloured strips.