Even though the precious metal gold only occurs very rarely indeed, it can be found almost everywhere on the planet in the 16 kilometre thick Earth’s crust. But the amount of gold in the earth is extremely small, so that mining is not really worthwhile. Generally there are two types of gold: primary gold (“mountain gold” from mines) and secondary gold (“stream gold” , “nuggets”). Above all the extraction of primary gold is associated with considerable effort. There are various methods to free the gold particles from their solid mantle in the ore extracted underground. The most important of these will be described here.