One of the hallmarks of genuine gold is just how heavy it is. However, scientists at the Swiss Federal Institute of Technology in Zurich have completely flipped this concept by creating a formation of gold that makes it 1000 times lighter than bullion of equal volume.
These lightweight properties come from aerogel – a porous, ultralight material created by removing the liquid component from a gel (which could be made by a variety of chemicals) and replacing it with a gas. According to their research, the scientists created gold aerogel by heating milk proteins until they began to form ultra-fine fibers, which were then placed in a solution of gold salts. The fibers interlaced themselves into a basic structure, onto which the gold simultaneously crystallized to form a gel-like network of gilded fibers. The scientists then used supercritical drying with carbon dioxide to remove the liquid from the gel without damaging the fiber network.
The result is a completely homogenous mixture of about 80% gold and 20% milk protein fibers (or, about 20kt gold). It looks solid to the naked eye, but because of its porous structure, gold aerogel is actually 98% air.
There are a few possible applications for this bizarre material. For instance, because gold aerogel is porous, it has a huge surface area – which could make it an extremely efficient catalyst.
