Its thickness is only one tenth of a millimeter, and ordinary people have no idea about this thickness. As a metal, it is opaque, but the edible gold foil is so thin that it is transparent to light, so even if it is described as "as thin as a cicada's wing", it is actually much thinner than a cicada's wing, and it will break under the tension of water, making it almost impossible to hold it by hand.
As an "imported" food, gold is not an ordinary brick, gold bar or gold ring. Gold used as food raw materials must be processed gold foil. According to legend, Ge Hong, an alchemist in the Jin Dynasty, created the gold foil process, which made pure gold undergo more than ten processes of fine processing, turning gold of different sizes into uniform gold foil as thin as cicada's wings, becoming a unique traditional process of the Chinese nation and being praised as "a must in China" in the world. This process can make a gold ring into a gold foil the size of a basketball court.
Later, gold foil technology spread to Japan and overseas, becoming the world's gold jewelry processing technology and lasting for a long time. Gold foil is widely used in antique buildings, modern buildings, gold plaques and so on. For example, gilding the Buddha statue, gilding the carved beam, and gilding it for decoration. Because it is as thin as cicada wings, it is the best choice as a food raw material.