if we see gold movement in bigger time frame, we may think that gold only about buy and buy, cause the graphics only showing the rising chart, but if you change the TF into the smaller one, you will see the same pattern like the currencies has. it also contain high and low. Gold have a very slow movement but stable for the long term. cause this reason, many traders choose not to trade gold. the more rare a currencies/ commodity to be trading, it will raise up the spread. so, big spread not only happened to gold but to all currencies and commodities that don't have an active trading session.