Materials

Lightweight, 18-Carat Gold Made from Plastic

ETH Zurich  researchers set out to create a new form of gold that weighs about five to ten times less than traditional 18-​carat gold. The conventional mixture for 18-carat gold is three-​quarters gold and one-​quarter copper, with a density of about 15 g/cm3. The ETH researchers created a lightweight 18-​carat gold using plastic instead of metallic alloy elements. Its density is only 1.7 g/cm3. The researchers used protein fibers and a polymer latex to form a matrix in which they embedded thin discs of gold nanocrystals. The lightweight gold also contains tiny air pockets that are invisible to the eye. It's suitable for chemical catalysis, electronics applications, and radiation shielding.