Authentic Murano Glass Blown in the furnaces of Murano. These are part of our Finestra (Window) line with opaque layers of ivory encased in trasparent Topaz with black filigrana which forms the windows with its clear sides. This is in the shape of a penny (a lentil or disc, but more flat) which measures approximately 30mm (approximately 1.18 inches) and about 12-14mm thick (like a cookie-penny). The hole size is a nominal 3mm in diameter but will vary because the maestro is blowing melting glass.