Colored glass is glass that has been infused with metal oxides or other materials to create a variety of hues. This process can occur during the glass-making stage, where different elements are added to the molten glass, or through surface treatments. The resulting glass can be transparent, translucent, or opaque, depending on the desired effect. Colored glass is often used in art, architecture, and decorative items. For example, stained glass windows in churches and cathedrals, such as those found in Notre-Dame Cathedral, showcase intricate designs and vibrant colors. Additionally, colored glass is popular in mosaics and glassware, enhancing both aesthetic appeal and functionality.