Researchers at ETH Zurich have accomplished a bit of modern-day alchemy, transforming 20 carat gold into a lightweight foam. Well, technically it's an aerogel: an exceedingly light and porous matrix of material. It's so porous, in fact, that the foam doesn't conduct electricity because, at atmospheric pressure, the gold atoms within the structure don't actually touch. "The so-called aerogel is a thousand times lighter than conventional gold alloys. It is lighter than water and almost as light as air," Raffaele Mezzenga, Professor of Food and Soft Materials at ETHZ, said in a statement.