Sommerso literally means "submerged" in Italian. As a technique it's about layering several colours of glass inside each other, so the finished piece has one colour inside and another — typically clear — outside.
How it's made
The glassblower starts with a small lump of coloured glass. It's dipped in molten glass of a different colour, which forms a layer around it. This can be repeated several times. Finally the whole thing is dipped in clear glass, so the inner colours appear to "float" inside a transparent shape.
The result is a piece that looks massive and heavy — and is. A sommerso vase is often twice as heavy as an ordinary vase of the same size, because most of the volume is solid glass.
What to look for
- **Clear layers with no bubbles between the colours.** Bubbles or unevenness between layers is bad craftsmanship — or fake.
- **A clear "edge" or shadow** that follows the transition between colours. That's the signature.
- **The weight.** Sommerso should be heavy. If it feels light, it isn't real.
When it peaked
The sommerso technique was used from the 1930s, but reached its peak in the 1950s and 60s. Seguso, Mandruzzato and Cenedese were among the masters. Many of the sommerso pieces you find at flea markets today are from that period.
Sommerso vs. cased glass
You'll also see "cased glass" — the English/American term for a similar idea. The difference is technical: cased glass usually has two layers (one colour inside, clear outside), while true sommerso often has three or more colour layers. In everyday language, though, the terms get used interchangeably.
