The Carlin-type gold deposits in Nevada, U.S., are the origin of five percent of the global production and 75 percent of the U.S. production of gold. In these deposits, gold does not occur in the form of nuggets or veins, but is hidden—together with arsenic—in pyrite, also known as “fool’s gold.” A team of scientists from the Helmholtz Centre Potsdam—German Research Centre for Geosciences GFZ has now shown experimentally, for the first time that the concentration of gold directly depends on the content of arsenic in the pyrite. The results were published in the journal Science Advances.