The growing popularity of white gold leads to interest in other coloured metals. Sterling silver cannot be alloyed for colour like gold, but there are many techniques to add colour to sterling pieces. Traditional methods like enamel, cloisonné, and inlay add a mosaic-like colour to silver jewellery. Patina brings out a darker, weathered look. It is even possible to paint right on the metal.
Sterling silver is defined as silver that is 92.5 per cent pure, usually combined with 7.5 per cent copper for strength. There are coloured silvers available, but more than 7.5 per cent of another metal is necessary to change silver from its usual white-grey colour. At this point, the coloured silver is no longer sterling.
Enamel is an ancient technique to add colour to metal. Depressions are made in the metal. Tiny bits of glass are added to these depressions, and the piece is heated up so the glass melts into place. This creates a translucent area of colour that the silver can still be seen through. It is possible to enamel areas with no metal underneath to create a stained glass effect, as well.
Sterling silver is difficult to enamel because it can develop a scaly look from exposure to heat. However, it is possible with practice and patience.
Cloisonné is related to enamel in that it uses the melted glass to create colour on top of metal. Partitions are created by laying metal wire pieces in a design, and the glass is placed in a partition and fired. The glass is laid in thin layers and built up until the height and colour desired is reached. Sterling silver often forms a base for the design, with gold wires for partitions, but it is possible to use silver wires as well.
Inlaying items is another way to add colour to silver. A setting is made from silver, and items such as shells are cut to shape and placed in these settings. They are held in with epoxy, and adding colour to the epoxy can change the shade of the shells. You can add a spot of colour or inlay simple or complex designs.
A patina is a layer of oxidation on the metal, due to age and exposure to air. It is a type of tarnish, but properly controlled it adds an antique look to silver. Silver's patina is dark or black. It can be left in crevices in a design to highlight the higher parts, which can be polished to a bright shine for contrast.
It is also possible to paint on metal. Use alcohol inks on silver to create a translucent colour that the metal can still shine through. Any painting on metal must be sealed or it will rub off. You can use epoxy resin to create a smooth, hard coat over the paint.
Resin can also be used in a manner similar to enamel and inlays. Pour coloured resin into depressions or settings in the silver and allow it to cure. The hardened resin will create a splash of colour like an inlay, but in a hard plastic.