Authentic Murano Glass Blown in the furnaces of Murano. These are part of our Finestra (Window) line with a base of ivory encased in with aventurina and aventurina filigrana which forms the windows with its transparent sides. This is in the shape of a sasso (pebble) a squashed round which measures approximately 20mm 3/4 inch across and similar in diameter. The hole size is a nominal 3mm in diameter but will vary because the maestro is blowing melting glass.