Murano Cased Glass Ashtray with Concentric Bubbles

Mid-century modern Italian / Murano art glass ash bowl with concentric bubble and sommerso decor. Click to learn more about Italian Glass. Beautiful mid-size ashtray from 1950s Italy.  The only signs of wear is on the flat polished base, tiny scratches called bottom-wear caused from surface friction over the years.  Can't be seen unless you look for it (see image 4). The Italians used manganese in the colorless glass recipes until the 1960s.  The mineral causes the colorless glass to glow a light greenish yellow under blacklight.  The colorless glass on this ashtray does glow, so we can date it to 1950 - 1960. The colorless glass was blown together with the emerald green glass (sommerso).  The tiny bubbles are perfect, a mark of a good artist.  The bubbles start small near the base and get slightly larger and they spiral upward. Unsigned. Measures 5" long on 3 sides and 2" tall.  Nice deep bowl.  Weighs 1½ lbs.