To make our cabinet knobs and pulls, 2 to 5 pieces of glass are cut, cleaned, stacked together and placed into a kiln. The kiln goes up to 1450 degrees Fahrenheit, the glass becomes molten and fuses together to make one piece of glass. The glass is then cut out out to the required shape. Next the glass is placed back into a kiln and taken to 1300 degrees fahrenheit and the edges are "fire polished". The glass spends about 48 hours in the kilns. Expect slight variations in color & size.Aquila Art Glass is proud to say "Our Glass Products are handcrafted in Portland Oregon using high quality handmade materials made in the USA."