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Precious Metals 101: Gold

You’re sitting at a table with a jewelry box that belonged to your grandmother. You open the lid and see all sorts of vintage treasures; tie tacks, sparkly earrings, pocket watches, coins, a charm bracelet with tiny, dangling pendants and baubles. While it all has sentimental value, you can’t help but wonder, “What is this worth?” 

That’s where a good understanding of precious metals comes in, and we’re here to deliver with a series devoted to these scarce, sought-after materials. Whether you’re assessing your own collection or hunting for treasure out in the wild, knowing the difference between precious and non-precious metals will come in handy. 

The elite Precious Metal Club is made up of three naturally occurring elements: gold, silver and platinum. Let’s start with good ol’ glamorous gold. 


As you know, gold is very valuable and highly sought after. Why? It’s rare, malleable and durable. Its malleability makes it an excellent material for coins, jewelry, decorative items and intricate detailing, and, because it doesn’t rust, oxidize or corrode, those items can have quite a lifespan. It doesn’t hurt that gold has been closely intertwined with currency for thousands of years. 

The Look 

Naturally yellow in color, the appearance of gold can be altered with the addition of secondary materials. For example, adding zinc or nickel leads to white gold, while adding copper creates the warm hue of rose gold. Additive alloys are used to create a spectrum of colors, from pink to green. Because of this, it’s important to take more than appearance into account when inspecting a suspected gold piece. 

The Purity

It’s essential to understand the gold purity system. The purity of gold is measured in karats, with 24k (or 99.9% gold) reigning as the purest. Simply put, the higher the purity, the higher the value. Now, how does the average buyer determine this? Luckily, modern gold is often stamped with a hallmark denoting its purity. Take a look at the table below:

Purity Hallmark Gold Content (wt. %) Purity % Hallmark
24k 99+ 990
22k 91.6 916
18k 75.0 750
14k 58.5 585
9k 37.5 375


Keep in mind that not all gold is marked. Antique, custom and altered pieces may lack identifying marks. That’s why Blue Moon Estate Sales pros are trained to identify and test precious metals to determine their purity and price them appropriately

You may notice a few other hallmarks as you’re inspecting pieces, specifically when it comes to jewelry. It’s common for makers to include a maker’s mark which can be especially exciting to identify. Other marks you may find may indicate that a piece is not solid gold, thus affecting its overall value. Such marks include:

Marking Meaning
GF Gold fill: A base metal with a bonded alloy layer of 10k or more
GP Gold plate: A base metal with a thin layer of gold chemically plated to the surface
GEP Gold electroplate: A base metal with a thin layer of gold electrochemically plated to the surface
RG Rolled gold: A base metal rolled in a thin coating of gold
RGP Rolled gold electroplate
HGE Heavy gold electroplate
925, STERLING or any other silver mark on a gold surface Vermeil: Silver coated in a thick gold alloy layer of 14k or more


Now that you have some valuable knowledge in your back pocket, you may want to take a look through your own collection. If you have any gold coins or jewelry you're looking to rehome, don't just pawn it off. Give us a shout. We can discuss your best options, including consignment.

We take our estate sale treasures seriously, especially when it comes to precious metals. We love nothing more than the thrill of the hunt so if you're looking to strike gold without spending a fortune, head out to a Blue Moon sale near you. We'll see you there!