Increase in gold prices is directly related to the world economies not doing well. Countries keep as gold as deposit with the world bank. Previously people use to buy dollars as everyone trusted American economy not to go down but after recession thats not the case and now people are more inclined to buy gold as it is a precious metal and it cannot be created.
And yea, anyone looking for an investment should always buy a mix of gold and silver. Silver has more industrial use than gold, so it will increase in value even when the economy of the country is doing well.(gold prices may take a hit that time)