Gold, like most heavy metals, are forged inside stars through a process called nuclear fusion. In the beginning, following the Big Bang, only two elements were formed: hydrogen and helium. This took with it the vast majority of the planet’s precious metals — such as gold and platinum.

How is gold mined and processed?

Gold that’s located farther below the surface is collected with underground mining methods. Large pieces of ore are made into smaller pieces, and then the sand grain-sized pieces are mixed with a cyanide solution to create a watery, mud-like mixture.

What type of geology is gold found in?

Gold is most often found in quartz rock. When quartz is found in gold bearings areas, it is possible that gold will be found as well. Quartz may be found as small stones in river beds or in large seams in hillsides.

What is the process of mining for gold?

As you can see, the process of taking metal ore from the earth and converting it to gold bullion is quite extensive and requires a lot front-end investment and time. In the end though, we get these shiny coins and bars to enjoy. Gold miners too take special care to make the impact of mining for gold as light as possible.

How is gold processed in a gold refinery?

Once basic processing is done, the ore is taken to a refinery where the remaining impurities are stripped out. Crude gold is melted and treated with chloride, which converts any remaining foreign metals to chloride which will then drift off the gold.

How does the Miller process increase the purity of gold?

The Miller process is rapid and simple, but it produces gold of only about 99.5 percent purity. The Wohlwill process increases purity to about 99.99 percent by electrolysis. In this process, a casting of impure gold is lowered into an electrolyte solution of hydrochloric acid and gold chloride.

How is gold made in the electrolytic process?

The carbon is treated for re-use. The electrolytic method of gold refining was first developed by Dr. Emil Wohlwill of Norddeutsche Affinerie in Hamburg in 1874. Dr. Wohlwill’s process is based on the solubility of gold, but the insolubility of silver, in an electrolyte solution of gold chloride (AuCl 3) in hydrochloric acid.