One of the most common questions I get is “What is an alloy?”
Those outside the jewelry biz often don’t know that even solid gold isn’t always ALL gold. Most jewelry is made from alloys.
An alloy is a mix of different metals that, when added together, give each other different properties. Some metals will add strength, while others will change the colour for example.
So when you look at a piece of jewelry that’s made with say, 14k gold, that means 14 parts pure gold, and 10 parts other metals – adding up to 24 parts.
Why 24? This system of measuring the proportion of gold in an alloy originated with a medieval coin called a mark, which weighed 24 karats.
So, pure gold is 24 karats – which is very rare in jewelry because it’s very soft and easily bent.
Okay, now that you know that the karat number represents the proportion of gold in the alloy, I’ll explain some of the most common alloys.
Most jewelry is made with 10k, 14k, or 18k gold. Which is 10, 14, or 18 parts gold respectively.
But there are different types of 14k gold! How does that work?
The different types of gold – usually different colours like yellow, rose, or white – are controlled by the other metals in the mix.
For example, 14k yellow gold is a mix of 14 parts gold and 10 parts copper and zinc, while 14k white gold is 14 parts gold mixed with nickel and zinc.
Phew, complicated, right?
Think of an alloy like a recipe for cookie dough. You can take the same cookie base and add cocoa to make chocolate cookies, or ginger and molasses to make ginger snaps, or oatmeal and raisins, or whatever type of cookie you want.
It’s the other ingredients that change the TYPE of cookie.
And gold isn’t the only metal that’s made into alloys. Sterling silver (the most common jewelry alloy) is a mix of silver and copper.
Silver alloys don’t follow the karat system but instead are measured in parts of 1000. Sterling is 925 parts silver and 75 parts copper – which is why it’s often marked with a 925 stamp.
Now I know that alloys aren’t just used in jewelry. There are also many industrial alloys – but I’m a jeweler so I’ll leave that up to someone else to explain.
That’s it for me, drop your questions in the comments!