Gold in its native state is found in quartz rocks, in the form of filaments, specks and foils, often mixed with silver minerals.

Or it can also be found in river beds, mixed with sand, in the form of grains and nuggets.

Gold mining

Gold extraction can be practiced with three different processes: smoothing , amalgamation and cyanidation . However, it is not always necessary to use all three processes.

The smoothing takes place using long containers, which allow the separation of the gold by letting a slow stream of water flow. In fact, the waste material, being lighter than gold, is dragged along with the water, while the small pieces of gold sink to the bottom of the container.

With amalgamation , raw materials are ground into a powder, which is then amalgamated with mercury. Subsequently, the precious metal is recovered by distilling the amalgam.

Cyanidation is the most important extraction process. Gold ores are treated with a solution of potassium cyanide, in the presence of air, the gold melts and turns into auro-potassium cyanide. The separation of the gold from this solution occurs with zinc and electrolytically.

Properties of gold

Gold in its native state is reddish yellow in color, lustrous, unalterable and malleable (the most malleable of metals). For this last reason and to allow it to be worked, it is alloyed with other metals. No common acid affects it except aqua regia, chlorine water, and alkaline cyanides. Its melting point is 1063° and boiling point at 2600°.

The largest gold producers are South Africa, China, the United States and Australia.