This is a type of glass that is the result of research carried out by Giulio Radi, the long-time (from 1939 to 1952) art director of the A.V.E.M. glass factory.

By exploiting the differences in the coefficients of expansion of the different types of glass and highlighting them through overlappings of gold and silver leaf, unusual chromatic effects are obtained and enhanced by submersion with layer of various thickness of transparent glass, mostly colourless, thus causing a kind of lens-like effect.
The items, surely high-level quality both referring to artistic expressions and to research, were mostly executed by the master glassblower Luciano Ferro. The XXXIII Venice Biennale dedicated a small retrospective exhibition to that items.
Maestro Aldo Nason took up this technique again by executing the fortunate "Yokohama" series of the 60s.