Shows the power of fear
A bogus rumour gets started that their Russian gold will be under the American embargo, and it instantly drops like a stone. After the truth comes out, it has to very slowly crawl back day by day to what it was, two steps forwards, one step back. Really! Embargo gold. Like that wouldn't be a piece of cake to get around, and probably on the market at a higher price with the longer market reaction to the restriction on the commodity.