A team of researchers have created real gold foam, a new form of the metal so light that it can sit on the tip of a feather, balance on the petals of a flower or float on the foam of your morning latte.

This lightest-ever form of gold was created by a team of scientists at ETH Zurich. Soft, shiny and malleable by hand, the gold foam, or aerogel, is indistinguishable from its heavier cousin to the naked eye. The gold foam is likely to have widespread applications beyond simple jewelry.

Gold has several remarkable properties that make it one of the most useful substances mined on Earth. It does not tarnish, is easy to shape, mixes readily with other metals to form alloys and conducts electricity well. It has a wide range of uses across the arts and sciences, from jewelry and gilding to medicine, dentistry, chemistry and technology, to name a few. Gold foam can be used in any of these industries; its malleability, light weight and porous structure will provide new avenues for innovation.

The 20-carat gold nugget created by the ETH Zurich team looks almost exactly like regular gold. It even retains gold’s characteristic color and shine. However, because gold foam is 98 percent air, it is light and can be reshaped by hand. Of the solid material, more than four-fifths consists of gold particles. The remaining material consists of thin strands of milk protein fibers that hold it all together.

In addition to creating a new form of gold, the team also created a new method for making it. After heating milk protein to produce the thin fibers they needed, the researchers immersed the fibers in a solution of gold salt. The protein fibers and the gold particles wove themselves into a basic, delicate network structure, which had to be dried gently with carbon dioxide instead of air. This process allows for a gold foam with the particles uniformly distributed, perfectly mimicking existing gold alloys. The technique also allows for a great level of control over the optical properties the gold will have, such as color and light absorption and reflection.