Platinum Hallmarks: What Do These Stamps and Markings Mean?

Platinum hallmarks are official stamps certifying purity (parts per thousand) in jewelry and other objects. They commonly indicate 950 (95% pure, standard for fine jewelry), 900, 850, or 999 (99.9% pure, for bullion).

Not all platinum is hallmarked, especially antique or very small pieces, or large investment-grade bullion.

Platinum hallmarks are often inconspicuous and hidden from plain sight. They’re essential for verifying authenticity and value, but their absence doesn’t automatically mean a supposed platinum item is fake.

Learn more right below!

• What are Platinum Hallmarks?
• Does All Platinum Jewelry Have a Hallmark?
• Does All Platinum Bullion Have a Hallmark?
• How To Check Platinum for Hallmarks and Purity?
• What is 999 Hallmark on Platinum?
• What is 950 Hallmark on Platinum?
• Does Platinum 900 Have its Own Hallmark?
• Does Platinum 850 Have its Own Hallmark?
  • What is the Dog Head Platinum Hallmark?
• Does Platinum 600 Have its Own Hallmark?
• Does Platinum 500 Have its Own Hallmark?
• Does Platinum/Iridium Alloy Has its Own Hallmark?
• Does Platinum Sterling Has its Own Hallmark?
• Can Platinum be Stamped “925”?
• Can Platinum be Stamped “750”?
• What are the Common Hallmarks on Platinum Watches?
• What Does the Stamp “958” on Platinum Mean?

Platinum Hallmarks: What Do These Stamps Mean?

What are Platinum Hallmarks?

Platinum hallmarks are official marks stamped on platinum jewelry and objects to confirm their purity and authenticity. These small stamps serve as guarantees the item contains the stated amount of platinum.

Common platinum hallmarks are:

• 950 – 95% pure platinum (most common for fine jewelry);
• 900 – 90% pure platinum;
• 850 – 85% pure platinum
• PLAT or PT – General indication of platinum content

Platinum hallmarks are important because platinum is often alloyed with other metals and hallmarks tell you exactly how much platinum you’re getting.

Does All Platinum Jewelry Have a Hallmark?

No, not all platinum jewelry is hallmarked.

While it’s typical for platinum jewelry to be hallmarked, especially in the US, UK and other countries with hallmarking regulations, not all platinum jewelry will have a hallmark.

For example, older, antique jewelry pieces from certain countries might not be hallmarked, and this doesn’t mean the platinum is fake.

Also, very small platinum items or those below a certain weight threshold may be exempt from hallmarking requirements.

Does All Platinum Bullion Have a Hallmark?

No, not all platinum bullion has a hallmark.

Platinum hallmarks are common on platinum jewelry to indicate purity and authenticity. But, they’re not always present on bullion bars, especially those produced for investment purposes.

Investment-grade platinum bars, especially those produced for large-scale investment purposes, are often considered raw material and not subject to the same hallmarking requirements as platinum jewelry.

How To Check Platinum for Hallmarks and Purity?

To check the purity and authenticity of platinum, look for symbols, hallmarks and stamps on the platinum pieces’ surface.

Platinum hallmarks are typically found on the inside or underside of the item (on clasps, bands, or handles) in inconspicuous places so as not to take away from the aesthetics of the jewelry piece.

Here’s an example of a platinum hallmark on a ring, conveniently hidden from view unless you specifically look for it and the ring isn’t on the wearer’s finger.

What is 999 Hallmark on Platinum?

A “999” hallmark on platinum indicates platinum is 99.9% pure (999 parts per thousand). 999 platinum is also known as 24 karat platinum and it’s the highest purity platinum form available and the one used for IRA-approved platinum bullion.

Meaning people wishing to open a platinum IRA account would be able to add 999 platinum coins and bars to their account.

Note: 100% platinum doesn’t exist as it’s technically impossible to prevent particles from other metals from contaminating pure platinum.

What is 950 Hallmark on Platinum?

A “950” hallmark on platinum indicates the piece of jewelry is 95% pure platinum (950 parts per thousand), with the remaining 5% consisting of other metals (iridium, ruthenium, or cobalt, which are added to improve the platinum’s properties for jewelry making.)

950 platinum is primarily used in jewelry, particularly for rings and other high-end pieces. It’s also used in some types of watches.

Beyond jewelry, it finds applications in laboratory equipment, electrical contacts, and the glass industry.

Does Platinum 900 Have its Own Hallmark?

Yes, platinum 900 has its own hallmark, which indicates its purity level. The “900” mark means the item contains 90% pure platinum, with the remaining 10% consisting of other alloys added for alloy strengthening.

The marking you find can vary depending on the country of origin.

• In the U.S. the hallmark will often be “900 Pt” or “Pt900”.
• In the U.K. the hallmark typically includes a fineness mark (the number “900”), an assay office mark, and a sponsor’s mark.

Does Platinum 850 Have its Own Hallmark?

Yes, platinum 850 has its own hallmark, which indicates that a piece of jewelry is 85% pure platinum. The 850 mark shows the millesimal fineness, or parts per thousand of pure platinum in the alloy.

The common hallmark is 850 Plat or 850 Pt.

In France, the “dog’s head” hallmark can be used to guarantee a minimum platinum purity of 85%.

Does Platinum 600 Have its Own Hallmark?

Yes, jewelry made from 600 platinum has its own specific hallmark, although the mark varies by region and is more descriptive than the hallmarks for higher-purity platinum alloys.

In the USA a piece with 60% platinum might be stamped 600Pt. 400(Other Metal), where “(Other Metal)” would be specified by the manufacturer, such as 600Pt./250Co./50Cu./50Zn./50Ni..

There’s no official hallmark for platinum 600 in the UK. The minimum legal fineness for a UK platinum hallmark is 850 parts per thousand.

Does Platinum 500 Have its Own Hallmark?

Yes, platinum 500 has its own hallmark, but it’s not widely accepted and recognized across the globe.

For example, there’s no official hallmark for platinum 500 in the UK. The minimum legal fineness for a UK platinum hallmark is 850 parts per thousand.

In the US, FTC guidelines stipulate the item must be marked to show both the percentage of pure platinum and the percentage of other metals for jewelry with a platinum content between 500 and 950 parts per thousand.

A piece with 50% platinum might be stamped 500Pt, 500(Other Metal), where “(Other Metal)” would be specified by the manufacturer, such as 500Pt./250Co./150Cu./50Zn./50Ni..

Does Platinum/Iridium Alloy Has its Own Hallmark?

Yes, platinum/iridium alloy is marked with a hallmark specific to it.

The marking includes the percentage of pure platinum (usually 90%), followed by an abbreviation for iridium, the metal it’s alloyed with.

Note: common metal ratios in platinum/iridium alloy include 90% platinum and 10% iridium, and 95% platinum and 5% iridium. These two are used in jewelry design.

70% platinum and 30% iridium is also possible but rare compared to the other two.

Does Platinum Sterling Has its Own Hallmark?

There’s no official or standardized hallmark specifically for platinum sterling. Platinum sterling is a hybrid alloy that doesn’t meet the legal fineness requirements for items to be stamped as platinum.

Platinum Sterling doesn’t qualify for a platinum hallmark as it contains a low percentage of platinum (sometimes as little as 3.5% to 5%) blended with sterling silver.

However, legally required marks must still be applied to indicate the metal content accurately.

For jewelry made of a platinum-sterling alloy, you’ll find a combination of sterling silver hallmarks like “sterling” or “925” and an additional stamp specifying the percentage of platinum, such as “5%Pt,” to disclose the full composition.

Can Platinum be Stamped “925”?

No, platinum can’t be stamped with the “925” hallmark. The “925” mark indicates that a piece is made of sterling silver. A piece stamped “925” contains 92.5% silver and 7.5% other metals, typically copper.

Remember that platinum and sterling silver are visually similar, and non-experts are often fooled by the two metals placed side by side.

Can Platinum be Stamped “750”?

No, platinum can’t be stamped with the “750” hallmark because this mark signifies 75% gold (18k).

The “750” mark indicates that a jewelry piece is made of 18k gold, meaning it’s made from 75% pure yellow gold and 25% other metals, mostly copper, zinc, silver and nickel.

Check out my gold hallmarks guide to learn more.

What are the Common Hallmarks on Platinum Watches?

Common hallmarks on platinum watches include fineness marks like “Pt950” or “950,” which indicate 95% pure platinum, and “Pt900” or “900” for 90% purity.

Other hallmarks include maker’s marks (also called sponsor marks) and assay office marks. These are symbols that verify the metal’s origin and quality through independent testing.

These marks are typically found on the inside of the case, bracelet, or lugs.

What Does the Stamp “958” on Platinum Mean?

The 958″ mark indicates that a piece is made of Britannia silver. A piece stamped “958” contains 95.8% silver and 4.2% other metals, typically copper.

But there’s 0% platinum in Britannia silver.

Remember that platinum and Britannia silver are visually similar, and non-experts are often fooled by the two metals placed side by side.

Platinum Hallmarks: What Do These Stamps Mean? Conclusion

Platinum hallmarks are official stamps that certify the purity and authenticity of platinum items.

These small marks indicate exactly how much platinum an item contains, a crucial info since platinum is often alloyed with other metals.

The most common hallmarks include 950 (95% pure platinum, standard for fine jewelry), 900 (90% pure), 850 (85% pure), and 999 (99.9% pure, used for investment-grade bullion).

Items may also be marked simply as “PLAT” or “PT” to indicate platinum content.

Not all platinum jewelry or bullion is hallmarked. While typical in countries with hallmarking regulations like the US and UK, antique pieces, very small items, or investment-grade bullion bars may lack these marks.

Hallmarks are usually found in inconspicuous locations, inside ring bands, on clasps, or on the underside of jewelry.

Check for proper platinum hallmarks when purchasing platinum items. This will help verify authenticity and true value of the piece you’re about to purchase.

Just remember that the absence of platinum markings doesn’t automatically mean an item is fake. This is especially true with older, antique or specialized pieces.

References:

• Silver or Platinum?- https://www.reddit.com/r/Hallmarks/comments/1azi3ot/silver_or_platinum/
• Platinum Ring- https://www.reddit.com/r/Hallmarks/comments/16wm6pz/platinum_ring/
• Anyone know what this stamp means? Supposedly made of platinum in the late 1930’s. No other stamps anywhere on the ring- https://www.reddit.com/r/jewelry/comments/s9s6pe/anyone_know_what_this_stamp_means_supposedly_made/
• Is this a common looking hallmark for a platinum ring? I’m only familiar with gold and silver marks- https://www.reddit.com/r/Platinum/comments/14sys6y/is_this_a_common_looking_hallmark_for_a_platinum/
• Platinum 600 Wedding Rings- https://kavalri.com.au/collections/platinum-600
• Platinum ring (850/1000) set with two old european cut diamo – Lot 88- https://www.maisonrc.com/en/lot/143853/23431551
• V -shaped No. 9.5 Ring PT900 Platinum x Diamond D0.36 Stamp about 4.3g V Character Ladies SA Rank- https://shop-nishikino7.com/en/products/v-shaped-9-5-ring-ring-pt900-platinum-x-diamond-d0-36-engraved-v-character-sa-rank
• Platinum Perfection Ring
  High Finish Flat Wedding Band Ring in 950 Platinum- https://www.tjc.co.uk/limited-stock-one-time-deal—950-platinum-fine-polished-band-ring-3191433.html
• Iridium Platinum Explained- https://www.georgianjewelry.com/blogs/news/iridium-platinum-explained
• 1930’s (?) platinum ring- https://www.reddit.com/r/Hallmarks/comments/1celnkg/1930s_platinum_ring/

• Platinum Wedding Band- https://www.newyorkestatejewelry.com/Platinum-Wedding-Band/Wedding-Bands/20222/4/item
• Platinum- https://www.langantiques.com/university/platinum-2/
• The Time+ Tide guide to universal hallmarks- https://timeandtidewatches.com/the-timetide-guide-to-universal-hallmarks/
• Platinum hallmarks chart- https://leonmege.com/leon-mege-hallmarks/