What do them carrots - er, karats - mean?

In our last post we touched on the value of gold and how it was historically considered the dominion of royalty, and for those who were considered the wealthy, the upper class, the rulers and merchant princes and robber barons. It was hard to find, took much effort and many resources to dig out of the ground, and was difficult to process into the pure metal that was so coveted. While used for early commerce in the form of coins, they were not common and most certainly not in the possession of the common people.

And then … along comes the Industrial Revolution. Suddenly the extraction of gold was much easier, making gold much more plentiful and readily available. With the increase in supply gold marketers saw an opportunity to meet a demand that had gone unfulfilled for centuries, even millennia: bringing gold to the masses. And, joy of joys, make more money!


The old way of mining and refining gave way to the new during the Industrial Revolution.


But pure gold was - and is - still expensive. So those who sold gold discovered they could make their gold go further by “diluting” it, or mixing it with other metals to make it go farther. Gold can be mixed with silver, zinc, or nickel, each of which is much cheaper than gold. This practice not only had the effect of extending the gold supply, but it also had the effect of lowering the price, making it cheaper. And as the price went down, it appealed to and was accessible by a much larger pool of customers. Instead of selling 1 kilogram of gold to a small number of wealthy customers they could sell 3 kilograms of gold to the wealthy AND to many, many more who were not wealthy. They also learned that adding different metals to the mix could change the color of the finished alloy. For example, rose gold has a higher content of copper, while white gold may have a higher concentration of silver or palladium.

But now there were different purities of gold that were in circulation. How to tell what was pure, and what was not? Some still wanted their gold to be pure, and it was, but how could it be easily identified to both those who were buying and those who were admiring? To identify the different levels of purity, a system was developed called “fineness”.

The fineness levels are indicated with a number, which is followed by a K (in the U.S.). The ‘K’ stands for karat (not to be confused with the Carat used to measure diamonds!). The karat is defined as a level of 41.666 fineness, out of 1000. So when 1000 is divided by 41.666, we get 24. So 24 karats equals a fineness of 1000 (or, more accurately, 999.9), which is pure, with no other metals other than trace amounts of other elements mixed in. So if we had a 1K, or 1 karat, gold thingy, it would be 4.166% gold and 95.834% other metals, and a 9 karat thingy would be 37.5% gold and 62.5% other metals.

This brings us to how purity is used in the gold we buy. The most common purities or fineness of gold sold in the U.S. are 10K, 14K, 18K, and the less-common 22K.

24K - Pure gold, baby! This is 99.9% pure, with no other metals mixed in (other than trace elements left from the refining process). This is typically not used in ordinary, every-day jewelry. It is too soft and will bend out of shape and picks up scratches very easily, so making something that is going to be worn in one’s day-to-day activity would be ill-advised. Most of the items held by the average buyer that are composed of 24K gold are coins, bars, and other investment-grade items that won’t be handled or worn much.

22K - Very high content of gold, 91.67%. This is the softest type of mixed-metal jewelry. The 8% content of other metal doesn’t sound like much, but it does make the jewelry much firmer. However, it is still very soft and will bend, break, and scuff or scratch fairly easily, so it is not used for daily-wear jewelry.

18K - 75% pure. This purity or fineness still has a very deep gold hue. It is still gentle on more sensitive skin, similar to the higher purities of 22K and 24K. However, because of its high gold content, it still scratches easily and would not be advisable for someone who is very active.

14K - 58.5% pure, and the most popular choice in the U.S. This is still mostly gold, but is much harder and more durable than higher purity gold jewelry. It doesn’t have the deep, yellow luster of the 18K, 22K, or 24K, but still looks like gold. It is a good choice for those who are more active or will be wearing their jewelry day in and day out. This is the best balance of price, durability, quality and purity, and appearance.

10K - 41.7% gold. Obviously, this is the least pure of the group and is, in fact, less gold than it is other metals. Because it is more other metals, it does not have quite the same appearance or luster that the higher purities lie the 18K or 22K do. Also, if a wearer has sensitive skin the other metals can irritate. On the plus side, it is the most affordable, making it available to a much larger customer base.