In gold trading, there is a big possibility to get big profit. Because the movement is faster then the currency pair and many people trade gold. Therefore the broker sets a high Gold spread because they get from the spread. and Gold is a very volatile trading instrument and can make movements of 100 pips in a few minutes or seconds when other currency pairs will only move 10-20 pips that's why brokers also charge higher spreads on gold because you can cover spreads from you trading very quickly and at the same time the broker can also get a good amount in spread