On the standard MetaTrader gold contract, 1.00 lot is 100 troy ounces, 0.10 lots is 10 ounces and 0.01 lots is 1 ounce, so a .00 gold move is worth about 00, 0 and respectively.
Position size = risk in account currency divided by (stop distance in dollars multiplied by ounces per lot). Check contract size, minimum lot, margin requirement and swap in the broker symbol specification before trading, as a minority of brokers use 10 ounces per lot.