Does Platinum Have A Stamp?

Does Platinum Have A Stamp?

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Bling, bling… that is an amazing ring! Is it made of platinum?


Are you sure?

Well, the jeweler I bought it from said that it was an 18K platinum ring.

There’s an easy way to find out if he was telling the truth or not. Look for the platinum hallmark, usually the word “PLAT” followed by two alphabets and three numbers. If you don’t find these stamped on the inside of the ring, we regret to inform you that the ring is a fake.

Pure platinum is too malleable and soft for practical applications like other precious, naturally occurring metals. Hence, it is mixed with an alloy for strength and durability. To help buyers identify what quality platinum they are buying, the jewelry comes with a hallmark that tells you about the white metal’s purity. This is how platinum’s value is calculated.

To see the most popular platinum jewelry just click here.

Now that you know how platinum is stamped, let’s look at a few other things you need to know about the hallmark:

The First Hallmark

In 1073, platinum was hallmarked for the first time. The law said that all precious metals need to be hallmarked. The only exemptions were gold weighing less than 1 gram, platinum less than 0.5 grams, palladium less than 1 gram, and silver less than 7.78 grams. During this time, platinum jewelry had no markings and simply had the words “Platinum” or “PLAT” stamped on it.

Finding a ring that is made of pure platinum can be difficult when you don’t know what you should be looking for. If you don’t find a marking, don’t be discouraged because this does not mean what you are buying is fake. You can always do a simple purity test to determine the quality of the jewelry. Moreover, you can and should ask for the certificate of authenticity, which a legal jeweler will carry.

Testing Your Platinum Jewelry

If you aren’t sure that the jewelry you bought is indeed platinum, here’s how you can test it:

Use a Magnet

A refrigerator magnet that is not strong enough to know whether your jewelry is real or a fake. Hence, we recommend buying a stronger one from a hardware store. Hold the jewelry close to the magnet and see what happens.

If the jewelry is gold, it won’t get attracted to the magnet. If it does, it is made of low-quality gold with more alloys. Only the clasp of the jewelry may stick to the magnet while the rest of the jewelry stays in a loose state. While this is a great way to find out if your jewelry is made of platinum or not, we recommend that you get it tested by a GIA expert.

Inspect the Hallmark

A hallmark is called a standard marking, which helps you identify what type of jewelry you are buying. The marking differs from metal to metal. Some hallmarks even tell you where the jewelry was manufactured, referred to as a markers mark. The most common places where you can find the hallmarks are inside the ring’s band or on the clasp of a necklace.

There’s even a hallmark on platinum coins, usually on the front and can be seen with a magnifying glass.

Purity Markings

As mentioned earlier, a hallmark usually tells you about the purity of the metal. Gold jewelry’s stamp shape is a rectangle with shaved-off corners, silver jewelry’s stamp shape is an oval, and platinum jewelry’s stamp shape is like a house.

The stamp number inside the shape is called millesimal. The hallmarks differ from country to country, so don’t be alarmed if you don’t see the same stamp on your UK-bought jewelry. Here’s how the purity markings work:

375 585850 900800 925
750 916950 999958 999
990 999

Purity Levels

Gold Purity StampPurityPlatinum Purity StampPuritySilver Purity StampPurity


Date Letter

The stamp numbers will tell you about the year the jewelry’s purity was tested and not when it was manufactured. Reading the numbers can be tricky since not all jewelry pieces have this number if it is a delicate ring or necklace. There’s just not enough room.

If the jewelry piece does have a date on it, it won’t be like a typical date. It will be in the form of alphabets and numbers. In 1478, all silver and gold artifacts were managed by the government. An alphabet was assigned every year to the jewelry pieces made in the next 25 years to prevent fraud. After this period, the alphabets were modified with letters and designs to prevent confusion.

Other Marks

There are a couple of other hallmarks too that you might see stamped on the jewelry.

GFGold Filled
KPKarat Plumb (This tells you that the jewelry is made of the karat mentioned or is perhaps more pure)
PPlumb Gold (This tells you about the jewelry’s karats)
Silver or SS or St SteelSterling Silver
PT or PLATPlatinum
CWCarat Weight (Indicates the weight of a gem or diamond)
SOLSolitaire Diamond
CZCubic Zirconia
4, 5, 6, 7, etc…Indicates ring size


Platinum has a stamp, often referred to as a hallmark. The hallmark differs from manufacturer to manufacturer. What remains consistent are the purity markings and the words “Platinum” or “PLAT” that indicate you are buying authentic platinum jewelry.

Keep in mind that platinum comes in multiple grades. There’s PL950/Iridium, which is 5% iridium and 95% platinum by weight, PL950/Ruthenium, which is 5% ruthenium and 95% platinum by weight and lastly, PL950/Cobalt, which is 5% cobalt and 95% platinum by weight. The higher quality platinum is PL950/Cobalt, high in purity, and contains a small percentage of hypoallergenic alloys.

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