When negotiating precious metals prices, watch out for this classic switcheroo: a dealer quotes you a price per ounce and references spot CME rates—but when you drill down and ask whether that's U.S. or Troy ounce, suddenly they claim U.S. ounces. Red flag. If they don't proactively clarify the unit of measurement upfront, they're banking on your confusion. The difference between a troy ounce (31.1g) and a U.S. ounce (28.35g) is real money. Before locking in any deal, make sure both parties are crystal clear on which standard applies. Don't let ambiguity slide—it's exactly how bad actors slip past honest traders.