There’s gold in that jewelry! But how much?
One of the issues that has come up many times over the years is just how much gold is actually in jewelry. In a recent article we discussed how much gold is in gold filled and gold plated jewelry, not much by the way, so I wanted to take some time to explain the various karat weights in jewelry.
What is a Karat?
The weight measure, karat, is actually tied loosely to the gem and diamond weight measure carat. A carat is a unit of weight equal to 0.20 grams (200 milligrams) but has it’s origins in ancient times where the carob seed was used as a unit of weight. The carob seeds were a uniform size and weight, and readily available so they made for a great scale to measure against. Over time the name of these seeds evolved to quirat and and eventually to carat.
The weight varied slightly over the ages until 1914 when the United States abandoned the 205 milligrams, 4 grains Troy weight, in favor of the current 200 milligrams. The bonus here is that if you have an older diamond originally sold using the older Troy weight you gained .005 milligrams in weight for every original carat!
Does Carat mean Karat? No, it doesn’t, but they are related. Back in “the day” the Germans had a coin called the mark. It was made from pure gold and weigh, wait for it, 24 carats. Over time the C changed to a K and the karat weight for gold as created with 24 karats being pure gold.
Gold Karat Weight
All of this brings us to karat weight and gold. When we talk about pure gold we are talking about 24 karat gold. Some jewelers and artists are making jewelry with 24k gold, and it is very popular in some cultures, but it is so soft that it makes a terrible metal for ring jewelry. Within days it will be scratched and dented so badly that you will never want to wear it. This is why we add alloys such as palladium or nickle (although not so much nickle these days), copper and silver to add durability to the soft metal. This is where the various karat weights come in to play.
As I said above, 24 karat gold is pure gold, so 14 karat gold is 14 parts gold and 10 parts alloy. 18 karat gold is 18 parts gold and 6 parts alloy, and so on. Until recently 10 karat gold jewelry was the lowest karat weight that could sold and still be called ‘gold jewelry’. Recently we have started seeing 9 karat gold being used.
All gold jewelry is required to have it’s gold content clearly marked somewhere on the piece. In the US we the traditional k or kt mark as in 14k (14kt). In Europe and Asia we use the percentage marking. 14k would be 585 for 58.5% gold. The chart on the right shows you the standard markings for gold jewelry.
As you can see, once you understand where the term comes from it starts to make more sense. Even though gold weight still uses an ancient system, it is based in some form of logic.