Nitro-cellulose enamels are also commonly known as modern lacquers. SnO has been used as pigment in the manufacture of glasses, enamels and ceramic glazes. It is also used in production of some ceramics, enamels, and ceramic glazes. ZnO affects the melting point and optical properties of the glazes, enamels, and ceramic formulations. In enamels and glazes it serves as an opacifier. It comprises over 1,400 pieces, including metalwork, enamels, lacquerwork and ceramics. Water-based acrylic polyurethane enamels are now almost universally used as the basecoat with a clearcoat. Classic alkyd enamels would fall into this category. Gold leaf or colored enamels also can be inlaid to highlight the designs. They were used for painted enamels on metal for the same reason. It is also used in the manufacturing of pharmaceuticals, fertilizers, dyes, explosives flares and enamels. The enamels of the edging alternate with gemstones. The badge of the Order of Friendship is made of gilded silver and enamels. Fired enamels adhere better to these alloys than to pure gold. This combined underglaze blue outlines with overglaze enamels in further colours.