Metal guide · November 2026
How do you check that a ring is really platinum?
Look for two marks, not one: the fineness number, such as 950, and an official hallmark struck by an assay office. The number alone is the seller’s claim; the hallmark is the independent check.
Updated 12 November 2026. By Alexey Kovernikov, owner of Kove Jewelry in Prague.
Platinum and white gold look almost the same, and a ring stamped "PT950" can still be something else. In Europe the answer is on the inside of the band, in small marks that say what the metal is and who vouches for it. This guide explains how to read them, with the Czech rules as the example, because that is where our rings are hallmarked.
Check a platinum ring in four steps
- 1
Find the number
Inside the band: 950, often written Pt950 or PT950. That is the fineness the maker declares.
- 2
Find the hallmark
An official mark from an assay office beside it. In Czechia a small crown with the digit 1 for platinum 950.
- 3
Find the identification mark
The mark of the company that answers for the piece. Czech law requires it, with a few exceptions.
- 4
Check the paperwork
The invoice names the metal and fineness, the diamond has its own laboratory report, and the seller is in the public register.
How Kove marks platinum
Every Kove piece in Platinum 950 is hallmarked by the Czech Assay Office (Puncovní úřad), exactly like our gold pieces, and carries our identification mark beside the hallmark. Kove Jewelry s.r.o. is in the office’s public register of makers and traders (search by IČO 27484611), record No. 15 432. Your invoice names the metal as Platinum 950.
The hallmark proves the metal, not the diamond. The centre diamond comes with its own IGI or GIA report, which you can check online by its number; how to do that is in our guide on checking an engagement ring online.
What 950, 900, 850 and 999 mean
The number is the share of pure platinum in 1,000 parts of the alloy. Pure platinum is too soft for a ring worn every day, so jewellery uses alloys, and 950 is the usual choice for engagement rings. Czech law (zákon 539/1992 Sb., § 3 and § 5) allows five platinum finenesses and gives each a digit that appears in the Czech hallmark. Anything below 800 is not legally platinum ware in Czechia.
| Fineness | Czech hallmark: digit and outline | CCM |
|---|---|---|
| 99999.9 % | 0 · circle | Yes |
| 95095 % | 1 · rectangle with an arched top | Yes |
| 90090 % | 2 · rectangle with arched sides | Yes |
| 85085 % | 3 · symmetrical hexagon | Yes |
| 80080 % | 4 · lens where two circles overlap | No |
Digits and outlines: vyhláška 363/2003 Sb., § 3. Convention finenesses: Hallmarking Convention.
What the Czech hallmark on platinum looks like
All Czech platinum hallmarks share one picture: a stylised royal crown. At the bottom of the crown sits the fineness as a single digit from 0 to 4, not as the number 950, and the outline around the crown changes with the fineness. Platinum 950 is digit 1 in a rectangle whose top side is arched (vyhláška 363/2003 Sb., § 3). A letter in the mark tells which branch of the office struck it (Puncovní úřad). The marks are tiny, so a loupe or a phone camera on zoom helps.
Next to the hallmark you will find the identification mark of the company that answers for the piece; with a few exceptions, Czech law requires it on every hallmarked article. Platinum pieces with no more than 0.5 g of platinum are exempt from compulsory hallmarking, but must still carry a number stating their fineness (zákon 539/1992 Sb., § 27 and § 28; vyhláška 363/2003 Sb., § 12).
The Convention mark: one hallmark for many countries
Czechia has been a party to the Hallmarking Convention since 1994. Its members can strike a Common Control Mark (CCM). In its classic form it shows balance scales with the fineness in parts per thousand, inside a shield whose shape shows the metal; a newer design was added in 2019. For platinum the recognised finenesses are 999, 950, 900 and 850 (Hallmarking Convention). A piece with the CCM is generally accepted in the other member states without being tested and marked again, as long as that fineness is legal there. The CCM is always struck together with the assay office’s own mark and a responsibility mark.
Why "PT950" alone is not proof
Anyone with a punch can stamp a number. The Czech Assay Office says it plainly: fineness numbers sometimes appear even on base-metal goods, so a number on its own does not tell you enough about the piece. A hallmark is different, because it is struck by an institution independent of both the maker and the seller (Puncovní úřad).
In the United States the rules work differently: the FTC jewelry guides set how a maker may mark platinum, for example "Plat.", "Pt." or "950Pt.". Those are the maker’s declarations. If you buy in Europe, ask for the official hallmark as well.
Designs you can order in platinum
Solène Cathedral Solitaire Oval
View the design
Entrelacé Twist Round
View the design
Lumière Sonnet Hidden Halo Oval
View the designShown in white gold; in platinum the design is the same and the white slightly softer and greyer. Open a design and choose Platinum 950 to see its price; it is made to order in up to 21 business days, the same as gold.
Platinum or platinum-plated?
A platinum-plated ring is base metal with a thin coating. It carries no platinum hallmark. Czech law forbids marking or selling base-metal articles with a precious-metal finish under the words gold, silver or platinum, and sellers must label them and display them separately (zákon 539/1992 Sb., § 40). A low price for a "platinum" ring is usually the first clue.
White gold is a separate case: it is a genuine precious metal, usually plated with rhodium for its bright white. It is hallmarked as gold (for example 585 or 750), never as platinum. How the two compare in everyday life is in our platinum vs white gold guide.
Questions people ask
What does 950 on a platinum ring mean?
That 950 parts in 1,000 of the alloy are platinum, 95 %. It is the usual fineness for platinum engagement rings. You may see it written as 950, Pt950 or PT950.
Is a PT950 stamp enough to prove a ring is platinum?
No. A number is what the maker declares, and the Czech Assay Office notes that such numbers sometimes appear even on base metal. The proof is an official hallmark struck by an independent assay office, such as the Czech crown mark or the Convention’s common control mark.
What does the Czech hallmark for platinum 950 look like?
A stylised royal crown with the digit 1 at its base, inside a rectangle whose top side is arched (vyhláška 363/2003 Sb., § 3). Czech platinum marks show the fineness as a digit from 0 to 4, not as the number 950.
Is 900 platinum worse than 950?
Both are genuine platinum and both are recognised by the Hallmarking Convention. 950 contains more platinum; how hard or soft a ring is depends on the whole alloy, not only on the number.
Can a platinum-plated ring be sold as platinum?
Not in Czechia. Base-metal articles with a precious-metal coating may not be marked or sold with the word platinum, and they must be labelled and displayed separately (zákon 539/1992 Sb., § 40).
Are Kove platinum rings hallmarked?
Yes. Every Kove piece in Platinum 950 is hallmarked by the Czech Assay Office, like our gold pieces, and carries our identification mark. The centre diamond has its own IGI or GIA report.
Next step
Sources
- Zákon č. 539/1992 Sb., o puncovnictví a zkoušení drahých kovů (puncovní zákon)
- Vyhláška č. 363/2003 Sb., kterou se provádějí některá ustanovení puncovního zákona, § 3 a § 12
- Puncovní úřad: Identifikační značky a puncovní značky
- Puncovní úřad: Registr výrobců a obchodníků (Kove Jewelry s.r.o., IČO 27484611)
- Convention on the Control and Marking of Articles of Precious Metals: how the Convention works, the Common Control Mark
- Hallmarking Convention: dates of accession of the Contracting States
- U.S. Federal Trade Commission, Guides for the Jewelry Industry, 16 CFR § 23.6 (platinum)
Still not sure? Just ask a real person.
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