Etched, gilded and silvered glass framed mirror. These mirrors are first etched, then gilded and finally silvered. The process of etching with a metal wheel was so intensive that each mirror took hundreds of hours. The process heated the wheel to the point that the glass could crack. The company took out a patent on the process they used to cool the wheel so they could do this amount of etching, without damaging the glass.Model #2668 c. 1960’s/70’s Shown in book; Cristal-Art La lavorazione del cristallo a torino Author Davide Alaimo p.85