Researchers with ETHzurich have successfully used plastic to create lightweight gold that retains its purity, according to a recent announcement from the institution. The lightweight gold is ideally suited for products like jewelry and watches — things that would benefit from a reduction in weight without a loss in gold purity or beauty.
The gold found in jewelry is made with metallic alloys that help reduce the weight, though some pieces of jewelry may still be too heavy to suit some buyers. The newly created 18-carat gold replaces the metallic alloy elements with a ‘matrix of plastic,’ reducing the density from a typical 15 g/cm3 to 1.7 g/cm3.
Polymer latex and protein fibers were key to creating this lightweight 18-carat gold, which the researchers say retains the same purity as its all-metal counterparts. Nanocrystals of gold were embedded as thin discs within the aforementioned plastic matrix, causing many invisible pockets of air that cut down the density and the weight.
As the video above demonstrates, this new type of gold sounds like plastic when it is dropped onto a surface. The researchers say it has the same material properties of plastic, but that it retains the metallic glimmer of gold, as well as workability for use in jewelry. It can also be polished just like ordinary gold.
Tweaking the composition of the gold enables the researchers to change the hardness of their product, as well. Lower temperatures are required to melt the plastic-based gold compared to the pure metal version, plus the shape of the nanoparticles enables the researchers to change the gold’s hue.
Patent applications for the gold material and the process to create it have been submitted.