Many bullion investors know that all gold is labeled with a purity. Most gold bars and coins have a purity of 999 or 9999, both of which qualify as investment grade. However, many investors are unaware of the process behind gold purification, and how the metal achieves this purity. Gold finesse, to put it simply, is all about gold purification.
Purification of a metal is the process of extracting the rock or mineral, and boiling it down to remove all other metals or substances except the remaining gold. Refining gold to the purest possible levels is a metal producer’s prime goal. Let’s talk about how the yellow metal achieves its gold standard.
How Gold Was Refined in Ancient Times
Fire was originally used to refine gold. Originally, this method of refining involved a metal smith, who, once gold was turned molten, would stir and skim the metal, continuing to remove impurities that rose to the top.
Gold Purification In Modern Times
Today’s gold refining process still shares some traits with original gold purification techniques, however the technology has been greatly modernized.
When gold ore is extracted from the earth, other minerals are attached to it. Usually gold is not very pure when mined, and is found in spots or veins that run through rocks. A huge quantity of soil or residue must be processed to find the tiniest amount of gold. In such situations, the first step in the refining process is physically separating the gold material from the earth or dirt attached. Sometimes this can be done with gold panning which is a simple process.
Next, either heat or chemicals can be used. Melting gold ore will result in the actual pure gold subsiding at the bottom of the liquid mixture, while the impurities rise to the surface. As the impurities continue to be skimmed off, the purity of the gold increases.
Today, most gold refineries use an advanced chemical technology to purify gold. The gold ore is placed into a chemical pool where an electrical current is shot through the structure. The electric current separates the gold from the impurities. Using this method, refineries are able to obtain purity levels of 9999 or higher.
There are many bullion bars and coins that are 99.99% pure (this is also known as 24 Karat). However, a lot of bullion is manufactured to be intentionally impure. Gold is a very soft metal, and coins or bars that are made with a high purity can scratch or damage easily. Often, mints or refineries will mix gold with an alloy (normally silver or copper), in order to make the coin more durable and help protect it.
An example of this would be pre-1933 era US gold coins, Mexican Gold Pesos, and SA Krugerrands. Even modern bullion gold coins today, such as the American Gold Eagle and South African Krugerrands contain a small amount of copper that makes the coin harder and less vulnerable to damage.