Gold is markedly more volatile than the FX majors, with XAUUSD daily ranges commonly running 1% to 2% of price and expanding sharply on CPI, NFP and FOMC days.
Because a standard lot is 100 ounces, a 0 gold move is ,000 per lot. Measure volatility with a 14-period ATR on your own broker feed, place stops beyond structure rather than inside the noise band, and let volatility change the lot size while risk per trade stays fixed.