Murrine Mosaic Vase (58.3.12): Venetian glass from the mid-20th century, like this piece by Paolo Venini, often has a somewhat unstable composition which means that the objects tend to get a buildup of alkalis on the surface making the surface slippery. The combination of the slippery surface and the often large size and heaviness of these objects make them difficult to handle while cleaning. Gift of Venini.