Counterfeiting precious metals is as old as money itself. Knowing how to spot fake gold starts with understanding how fakes are made. In September 2012, Manhattan dealer Ibrahim Fadl paid $100,000 for four 10-ounce PAMP Suisse gold bars. He drilled into them after a colleague’s tip — and found tungsten [NBC News]. The bars had already passed X-ray fluorescence testing and a scale check. With gold near all-time highs, the incentive for this kind of fraud has never been greater. The good news: most fakes can be caught before money changes hands. This guide covers how counterfeits are made, which tests work, what