Authentic Murano Glass Blown in the furnaces of Murano. These are part of our Finestra (Window) line with transparent Amethyst (purple) and black filigrana which forms the windows with its clear sides. This is in the shape of a "sasso" (in English a pebble) which measures approximately 30mm (approximately 1.18 inches) across as well as at the largest diameter. The hole size is a nominal 3mm in diameter but will vary because the maestro is blowing melting glass.