Orsoni Furnace is one of the last working mosaic and glass-colour workshops left in Venice. Since the late 19th century it has produced smalti and gold-leaf mosaic tiles using traditional methods, the kind of craft usually hidden behind the finished splendour of Venetian churches and palaces.
Visits are limited, so check ahead rather than simply turning up. Even a short tour is worthwhile if you want to see Venice as a place where skilled work still happens, not only as a stage set for visitors.