"From the mid-1920's through to the 1940's glass knives were part and parcel of most complete kitchens. It was an era in which most everything imaginable was made out of glass -- from mail boxes to tableware to floor lamps to serving trays to dresses! Ranging in size from about 7-1/2 to 9-1/2" these glass knives were most commonly made in crystal [the Depression Glass collector term for transparent uncolored glass], but were also available in amber, blue, green, pink, and white. Now, why would one ever want a knife made out of glass you may ask? The best answer comes from an original advertisement for the "DUR-X GLASS FRUIT and CAKE KNIFE" a gadget designed and patented by a certain John Didio of Buffalo, New York in November 1938"