Fool's gold

"Fool's gold" refers to a mineral called pyrite, which has a shiny, yellow appearance similar to gold. However, unlike gold, pyrite is not valuable or precious. It gained its name "fool's gold" because people who are not knowledgeable about minerals might mistake it for genuine gold. The phrase is often used metaphorically to describe something that may seem valuable or promising at first glance, but upon closer inspection, turns out to be worthless or deceptive.