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Understanding international platinum hallmarks meaning for sellers is one of the most practical skills you can develop before buying or offloading platinum jewelry, coins, or scrap. These small stamps tell you exactly what the metal is worth – and whether a piece is legitimate.
Platinum is notoriously difficult to identify by sight. It looks like white gold, silver, and even palladium. Without a hallmark, you are guessing. With one, you have a legal record of purity that travels across borders, holds up in transactions, and directly determines melt value. This guide breaks down every major mark you will encounter, explains what they mean for pricing, and shows how to use that knowledge when you sell platinum jewelry or scrap.
Why International Hallmarks Matter for Platinum Sellers
A hallmark is not decoration. It is a legally recognized stamp applied by an independent assay office after the metal has been tested and confirmed to meet a specific purity standard.
For platinum sellers, this matters because the metal’s value is entirely tied to purity. A piece marked 950 contains 95% pure platinum. A piece marked 850 contains 85%. At a spot price of $1,610 per ounce (at the time of writing), that difference is significant on any piece with real weight.
The system works internationally because most major trading nations joined the International Convention on Hallmarks. Member countries agreed to recognize each other’s assay marks as legally valid. That means a platinum ring hallmarked in France, Germany, Japan, or the US carries the same legal standing in the UK – and in most convention countries – as a domestically hallmarked piece. Sellers do not need to pay for a new assay when crossing borders.
The UK formalized mandatory platinum hallmarking through the Hallmarking Act of 1973, which requires all platinum items over 0.5 grams sold in the UK to carry a hallmark. The UK became a signatory to the international convention in 1972, one year before that law took effect.
The Three Compulsory Stamps on Any Valid Platinum Hallmark
Every legitimate platinum hallmark includes three required stamps. If any are missing, treat the piece with caution.
The fineness mark is the most important number for pricing. In the UK, it appears inside a five-sided pentagon shape – this distinguishes platinum from gold and silver, which use different outline shapes. If you see a purity number in a circle or oval, double-check whether the piece is actually platinum or a silver alloy.
Three optional stamps also appear on many pieces: a traditional fineness symbol (the orb – a circle with a cross – often indicates 950 or 999 purity), a date letter showing the hallmarking year, and the Common Control Mark (CCM).
The CCM is the key to international validity. It shows a balance scale inside a diamond shape. When you see this mark, the piece has been hallmarked under the international convention and is legally recognized in every member country. No re-assay needed.
ℹ️ Info: The CCM (balance scale in a diamond) is your fastest confirmation that a platinum piece from another country is internationally valid. If it’s present, you can proceed with confidence in any convention country.
Decoding Fineness Numbers: What Each Stamp Means for Value
The number on a platinum piece is not arbitrary. It tells you the exact proportion of pure platinum in the alloy, expressed in parts per thousand.
Fineness
Purity %
Common Use
Seller Notes
850
85%
Budget jewelry, some European pieces
Must be stamped “850 Plat” – lower melt value
900
90%
Some European and Asian jewelry
Stamped “900 Pt” or “PT900”
950
95%
Standard for fine jewelry worldwide
Most common – can be stamped just “Platinum” if ≥95%
999
99.9%
High-end pieces, bullion
May show the orb mark – highest melt value
The US and UK share the same rule: if a piece is 95% pure or higher, it can legally be stamped simply as “Platinum” with no number. If purity falls between 85% and 95%, the number must appear. A piece stamped just “Platinum” that tests below 95% is fraudulent.
Watch for mixed alloy stamps. Some pieces contain multiple platinum-group metals. A piece with 60% platinum and 35% iridium would be stamped “600 Plat 350 Irid”. The total platinum-group content is high, but the pure platinum content is lower than a straight 950 piece. This affects melt value directly.
Once you know the fineness, calculating melt value is straightforward.
How to Calculate Platinum Melt Value
1
Step 1 – Weigh the piece Get the weight in grams using a precision scale
2
Step 2 – Apply the fineness Multiply weight by the purity decimal (e.g., 0.95 for 950)
3
Step 3 – Convert to ounces Divide the result by 31.1 (grams per troy ounce)
4
Step 4 – Multiply by spot price Use the current platinum spot price per ounce
Example: A 10-gram ring marked 950 Pt. Pure platinum weight = 10g x 0.95 = 9.5g Convert: 9.5 ÷ 31.1 = 0.305 troy oz Melt value = 0.305 x $1,610 = approximately $491 (at the time of writing)
That same ring marked 850 would yield about $439 – a $52 difference on a single piece, before any other factors.
Melt value is the floor, not the ceiling. A well-made piece from a recognized designer, or one in excellent condition, can sell for more. But melt value tells you the minimum a legitimate buyer should offer.
Different countries use different visual formats, but the fineness numbers stay consistent across the convention.
United Kingdom: Fineness in a pentagon, assay office mark (lion, castle, or thistle), sponsor mark. Date letters have been standardized since 1975. Convention mark appears as the CCM balance scale in a diamond.
United States: Uses numeric stamps like “950 Pt” or “PT950.” The US is a convention member, so US-hallmarked pieces are valid in the UK. American pieces often skip the assay office mark in favor of the maker’s mark and fineness stamp.
Japan: Japanese platinum jewelry is almost always marked PT950 or PT900 – the “PT” prefix is a reliable indicator. Japanese silver is also frequently 950 fineness, so the PT prefix is what separates them. Without it, the shape of the fineness mark becomes critical.
Mexico: Mexican silver is often 950 fineness, which creates real confusion at the point of sale. Look for “PT” or the pentagon shape. If neither is present, request an XRF test before assuming the piece is platinum.
France and Germany: Both are convention members. French pieces often carry the maker’s mark, a French eagle head (gold guarantee mark), and the fineness stamp. German pieces follow the CCM system closely. Both are legally valid in the UK without re-hallmarking.
⚠️ Warning: Mexico and Japan both produce high-fineness silver (950) that can look identical to platinum stamps. Always check for the “PT” prefix or pentagon outline before pricing a piece as platinum.
Special Cases: Bullion, Antiques, and Unmarked Pieces
Not every platinum piece requires a hallmark – and knowing the exceptions protects sellers from unnecessary suspicion or missed opportunities.
Platinum bullion bars are raw material, not jewelry. They do not require hallmarking under the legislation. A 1 oz platinum bar with no assay stamp is not automatically suspect – it is likely bullion. Check for a mint stamp, weight, and fineness engraving instead. Reputable mints like Argor-Heraeus engrave these details directly.
Pre-1950 antiques occupy a gray area. Items made before 1950 can be sold as precious metal without a hallmark, provided the seller can demonstrate purity and approximate age. This is a legitimate exemption used in antique jewelry sales, but it is also a common cover for misrepresented pieces. If a seller claims antique status to explain a missing hallmark, ask for documentation or request an independent assay.
Items under 0.5 grams are exempt from mandatory hallmarking in the UK. A tiny platinum charm or finding with no stamp may be entirely legitimate. Weigh it first – if it clears 0.5 grams and still has no mark, that is a concern.
Common Misconceptions That Cost Sellers Money
“All platinum is 95% pure.” It is not. Pieces range from 85% to 99.9%. Always read the number. A 10-gram piece at 850 is worth meaningfully less than the same weight at 950.
“A hallmark means the whole piece is high quality.” The hallmark only covers platinum purity. The other metals in the alloy – nickel, cobalt, copper, iridium – vary in quality and cost. Two 950 Pt rings can differ significantly in durability and resale value depending on what makes up the remaining 5%.
“Foreign hallmarks aren’t valid here.” Convention hallmarks from member countries are legally recognized. A French or German stamp is just as valid as a British one. Sellers who pay for unnecessary re-assaying are wasting money.
“Platinum is always worth more than gold.” Not currently. At the time of writing, platinum spot is around $1,610 per ounce, while gold sits near $4,106 per ounce. Gold is more than twice as expensive per ounce right now. Platinum jewelry often carries higher manufacturing costs due to the metal’s density and working difficulty, but raw melt value currently favors gold.
“Silver and platinum look the same, so the stamp doesn’t matter.” The stamp is exactly why it matters. Both are silver-white metals. Without the fineness mark and its shape, visual identification is unreliable. The pentagon shape and PT prefix exist precisely because these metals are so easily confused.
For a broader comparison of how platinum and gold stack up at the point of sale, platinum vs gold selling strategies covers the key differences.
Practical Checklist Before Selling an International Platinum Piece
Is This Piece Valid for Sale?
Is there a fineness number (850, 900, 950, or 999)?
Yes – proceed. No – request assay or documentation.
Is the number inside a pentagon shape?
Yes – UK-standard platinum mark. No – may be gold or silver.
Is there a CCM (balance scale in diamond)?
Yes – internationally valid, no re-assay needed. No – check for national assay mark.
Does it say “Platinum” with no number?
Must be ≥95% pure to be legal. If in doubt, test it.
Does it weigh over 0.5 grams?
Yes – hallmark should be present. No – exemption may apply.
Is the seller claiming it’s pre-1950 antique?
Ask for documentation or independent assay.
How Accurate Precious Metals Handles International Platinum
When you bring a platinum piece to Accurate Precious Metals – whether it was made in Tokyo, Paris, or Salem – the process is the same. The team assesses the piece for metal content using XRF analysis, checks the hallmark against the fineness reading, and makes a competitive offer based on current spot prices.
Accurate Precious Metals has been buying and selling precious metals since 2012, with more than 1,000 five-star reviews from customers across the country. The team handles everything from fine platinum jewelry and bullion bars to scrap and broken pieces – no condition is too rough to evaluate.
If you are local to Salem, Oregon, you can bring your platinum in person for a face-to-face assessment. If you are anywhere else in the US, the mail-in service makes it just as easy. You receive a free insured shipping kit, your pieces are thoroughly examined on arrival, and payment moves quickly. There is no guesswork and no pressure. Learn more about mailing in your platinum for a cash offer if you are outside the Pacific Northwest.
Accurate Precious Metals is not a pawn shop. It is a specialized precious metals dealer with the expertise to read international hallmarks correctly and price pieces accordingly. That distinction matters when you are holding a piece stamped PT950 from a Japanese jeweler – a generalist buyer might undervalue it or reject it outright. Accurate Precious Metals knows what the stamp means and prices it fairly.
Whether you are selling a single platinum wedding band or a collection of international pieces, getting a fair price for platinum jewelry starts with knowing what your hallmarks say – and working with a buyer who knows how to read them.
Frequently Asked Questions
What does 950 mean on platinum jewelry?
It means the piece is 95% pure platinum, with the remaining 5% made up of other metals. This is the most common purity standard for fine platinum jewelry worldwide. At a spot price of $1,610 per ounce (at the time of writing), a 10-gram 950 piece has a melt value of approximately $491.
Are platinum hallmarks from Japan or France valid in the US and UK?
Yes. Both Japan and France are members of the International Convention on Hallmarks. Pieces bearing a Common Control Mark – the balance scale inside a diamond shape – are legally recognized in all member countries without re-assaying.
How do I tell platinum apart from silver if both are marked 950?
Look for the "PT" prefix (e.g., PT950) and the pentagon-shaped outline around the fineness number. Silver uses different outline shapes. If you are still unsure, request an XRF test, which measures actual metal composition.
Does platinum bullion need a hallmark?
No. Platinum bullion bars are classified as raw material and are exempt from hallmarking requirements. They typically carry a mint stamp, weight, and fineness engraving instead of a traditional assay hallmark.
Can I sell a platinum piece with no hallmark?
Possibly. Items under 0.5 grams are exempt from mandatory hallmarking. Antique pieces made before 1950 may also be sold without a mark if purity can be demonstrated. For anything else, an independent assay establishes value and legitimacy before sale.
What is the CCM and why does it matter?
The Common Control Mark is a balance scale inside a diamond-shaped outline, accompanied by the fineness number. It confirms the piece was hallmarked under the International Convention, making it legally valid in all member countries. It is the fastest way to confirm international legitimacy without additional testing.
How does platinum spot price affect what I receive when selling?
Melt value is calculated directly from spot price, weight, and fineness. Higher spot prices mean higher offers. At $1,610 per ounce (at the time of writing), a 950 piece weighing one troy ounce has a melt value of about $1,530. Final offers also reflect condition, craftsmanship, and current demand.
Make the smart choice — invest with Accurate Precious Metals
Whether you are buying bullion for the first time or adding to a long-term position, our team offers expert guidance, transparent pricing, and a reliable buyback program.
