A new take on the Midas touch - changing the colour of gold

Red gold, green gold - a ground-breaking initiative has found a way of changing the colour of the world's most iconic precious metal.

A University of Southampton team has discovered that by embossing tiny raised or indented patterns on to gold surfaces they can change the way it absorbs and reflects light - ensuring our eyes don't see it as 'golden' in colour at all.

The finding results from a major initiative funded by the Engineering and Physical Sciences Research Council (EPSRC) targeting the development of a new generation of nanotechnology-enabled materials.

Equally applicable to other metals such as silver and aluminium, this breakthrough opens up the prospect of colouring metals without having to coat or chemically treat them. This could deliver valuable economic, environmental and other benefits.

The technique could be harnessed in a wide range of industries for anything from manufacturing jewellery to making banknotes and documents harder to forge.

''This is the first time the visible colour of metal has been changed in this way,'' says Professor Nikolay Zheludev, deputy director of Southampton's Optoelectronics Research Centre, who led the project.