That's weak. You get your gold certified, and it is not difficult to send it through a series of tests. Skin tests, water tests, magnetic tests. There are established physics relating to the weight of gold, and these are well documented. When combined with proper certification, e.g. a reputably and recognizably minted coin, or print on bars with certification, it becomes a high trust precious metal very easily.

Trading in gold becomes difficult, especially if there is no way to mint a currency from your metal, but verifying that your gold is real gold is not very difficult and most gold you would obtain is properly certified in some fashion anyway as you aren't the one mining it and purifying it of impurities.