Murano glass is glass made on the Venetian island of Murano, which has specialized in glassware for centuries. Murano’s glassmakers led Europe for centuries, developing or refining many technologies including crystalline glass, enamelled glass (smalto), goldstone, multicolored glass (millefiori), milk glass (lattimo), and imitation gemstones made of glass. Today, the artisans of Murano continue these centuries-old techniques, crafting figurines, chandeliers, glassware and vases, contemporary art glass, beads, and tourist souvenirs.Today, Murano is home to a vast number of factories and a few individual artists' studios making all manner of glass objects from mass marketed stemware to original sculpture. The Museo del Vetro (Glass Museum) in the Palazzo Giustinian houses displays on the history of glassmaking as well as glass samples ranging from Egyptian times through the present day. The other raw materials, called flux or melting agents, allow glass to soften at lower temperatures. The more sodium oxide present in the glass, the slower it solidifies. This is important for hand-working because it allows the glassmaker more time to shape the material. The various raw materials that an artisan might add to a glass mixture are sodium (to make the glass surface opaque), nitrate and arsenic (to eliminate bubbles) and coloring or opacifying substances.