How to separate gold from sand using mercury?

i need to know the method, the environmental problems created, and the physical properties involved.How to separate gold from sand using mercury?The physical properties this method is based on are (1) mercury is a liquid with density 13.534 鈥塯/cm鲁; and (2) Gold is a solid with density 19.3 鈥塯/cm鲁, much greater than mercury, and sand is solid largely of SiO2 with density 2.2 g/cm鲁, much less than mercury.

Simply put gold and sand into mercury. sand would float to the top and gold would sink down.

However, please never use this method to separate sand and gold. Mercury and its vapor are very poisonous. Mercury may also seek into SiO2 sand and make the contaminated sand very poisonous.How to separate gold from sand using mercury?The process of using mercury to separate gold from sands is called "Amalgamation." It is not a gravity based separation! It is in fact a chemical reaction. The mercury alloys or forms an amalgam with the gold - basically, the gold is dissolved into the mercury. This amalgam, which is a thick solution/paste of gold in mercury is then heated (retorted) to yield a gold sponge like material. It should be noted that this process is not healthy to you or the environment.