How "pure" is pure 999.99 gold?

While in colloquial language, “pure gold” refers to something excellent, genuine, or perfect, in the world of gold, pure gold means 24-carat gold, which is usually marked as 999 (99.9%). Still, how pure is this gold, and why isn’t the sample of the purest gold, for example, 1000 or 100%?

Is pure gold still pure?

The purity of gold is in fact nothing more than the content of gold in the corresponding alloy, usually expressed in carats or percentages. It is the number of carats or the percentage of gold in a sample that shows how much of the alloy is gold and how many other metals it contains, such as copper, palladium, zinc, silver or nickel. As has been said, 24-carat gold means pure gold.

The sample of 24-carat gold is 999, which means that it is an alloy of 99.9% gold, not 100%, as might be expected at first glance. But why: does this mean that pure gold is not pure?

The answer to the question of why gold is not 100% pure stems from the specific nature of the gold industry and is logical: in particular, it is practically impossible to guarantee the removal of 100% of all additional elements that gold may be exposed to during processing.

Even more important reason, however, is that the removal of additives from a certain limit also becomes unreasonable. The removal of the last fraction of the substances is the most costly part of the process, and in a situation where the removal of the last part does not provide equivalent added value to the cost, such an operation is just not economically justified.

Pure gold and other gold samples

The decision on which sample of gold to use for a particular product will depend in particular on its future function. For example, pure gold is not usually made into jewellery, because pure gold is a very soft material and there is a high risk that pure gold jewellery will deform.

In the case of jewellery, therefore, the usual samples are 750, 585 and 375. Historical coins are not made of pure gold either – in order to ensure the durability and wear resistance of the coins, alloys were also used to mint gold coins. Therefore, 900 or 917, rather than 999, samples are often used for historical gold coins.

As gold is no longer used every day as payment and wear resistance is no longer a very important criterion, modern gold bullion coins and bars usually carry 999 samples and are produced in the vast majority of investment products.

Investment gold is used primarily for the purpose of preserving assets, but very often also as a means of enriching the portfolio. As gold is very weakly linked to other asset classes and global economic cycles, it will firmly protect the investor from higher losses or a sudden free fall.