Many items made using precious metals, such as jewelry or bars, bear various stamps of numbers, letters, or specific symbols. Each stamp represents essential information about the object that jewelers, precious metal buyers, and other individuals can use to identify it and estimate its value.
Understanding the various stamps on precious metal objects, how to find them, and what each type means can help you determine the worth of your pieces and whether they are authentic.
But don’t worry if you can’t find a specific marking. At AU Precious Metals, we can professionally test your items’ purity and melt value using our cutting-edge X-ray technology, so you can confidentially turn your precious metals into cash.
What Are Stamps on Precious Metal Items?
Stamps on bars and jewelry made using precious metals are typically referred to as hallmarks. The primary role of a hallmark is to identify the object’s origin and composition.
Although hallmarking is an ancient tradition dating back to Antiquity, the first instance of modern hallmarking appeared in France in the 13th century, with the passage of the Goldsmiths Statute of 1260 under King Louis IX and the establishment of the first assay offices.
Hallmarking is often referred to as the oldest form of consumer protection. Hallmarks serve as an identification mark proving that an object contains the advertised type and quantity of precious metals. Historically, hallmarking was used to identify gold and silver objects. However, modern assay offices also typically stamp palladium and platinum.
Types of Precious Metal Stamps
There are five main categories of hallmarks on precious metal objects: fineness marks, maker’s marks, sponsor’s marks, assay office marks, and date letters.
1. Fineness Marks
Fineness marks are used to identify the type of precious metal used in jewelry and bars and the purity of the object’s special metal content. The mark is composed of strings of three numbers without decimals, with specific exceptions depending on the precious metals used.
Each precious metal is assigned a specific shape in which a three-digit code is stamped to identify the metal’s purity. The three-digit code represents the purity in parts per thousand.
For example, 925 on silver jewelry indicates it is sterling silver, 92.5% pure silver. Gold jewelry advertised as 18-karat gold may have a 750 purity code, as “18 karats” means 18 parts (75%) pure gold and six parts (25%) base metals.
Stamps commonly seen on jewelry, such as gold rings or silver necklaces, include:
| Metal | Symbol Shape | Common Purity Codes |
|---|---|---|
| Silver | Oval | 800, 925, 958, 999 |
| Gold | Rectangular Octagon | 375, 585, 750, 916, 990, 999 |
| Platinum | Boxy, house-shaped | 850, 900, 950, 999 |
| Palladium | Trapezoid (until 2009) or Three Circles (2010 onwards) | 500, 950, 999 |
- Silver items feature an oval symbol. Common silver purity codes include 800, 925 (sterling silver), 958 (Britannia silver), and 999 (three-nines fine silver).
- Gold items feature a rectangular octagon symbol. Commonly-seen gold purity codes include 375 (9 karat gold), 585 (14 karat), 750 (18 karat), 916 (22 karat), 990, and 999 (24 karat).
- Platinum items feature a boxy, house-shaped symbol. Typical platinum purity codes include 850, 900, 950, and 999.
- Palladium items manufactured until 2009 were stamped with a trapezoid shape. From 2010 onwards, they feature three circles instead, one for each digit of the purity code. Commonly-found palladium purity codes include 500, 950, and 999.
2. Fineness Marks on Bars
Bullion bars, such as gold or silver bars, typically feature stamps identifying which precious metal they are made of in plain letters (e.g., “Silver” or “Fine gold”) alongside a fineness mark. On bars, purity codes may feature decimals. For example, a bar of fine silver with a purity code of 999,9 means it is 99.99% pure.
3. Plated Jewelry
Jewelry made using precious metal plating may or may not feature hallmarking, depending on the precious metal content and country of origin. For example, according to the British Hallmarking Guidance Notes, jewelry produced in the United Kingdom may not be hallmarked if the item is made of base metal, even if the plating is a precious metal.
If an item is made using one precious metal but plated in another, that item may only feature hallmarking corresponding to the first metal—for example, silver hallmarks on a gold-plated silver ring.
4. Maker’s Marks and Sponsor’s Marks
A maker’s mark is a unique stamp identifying the precious metal object’s manufacturer. If the entity responsible for sending that object to an assay office for hallmarking isn’t the manufacturer, then the mark is referred to as a sponsor’s mark. Sponsors include importers, wholesalers, and retailers.
Although maker’s and sponsor’s marks can have different shapes, they typically feature one, two, or three letters stamped inside various shapes or shields. Common marks may feature an individual’s initials or letters representing a company’s name, depending on the entity represented.
Only an entity registered with an assay office can have a maker’s or sponsor’s mark stamped on a precious metal item.
5. Assay Office Marks
Assay offices are accredited precious metal assaying organizations. They issue stamps of authenticity on a precious metal object after testing and verifying its composition.
In addition to fineness marks and either a maker’s mark or a sponsor’s mark, many objects may also feature assay office marks. This type of mark is common in European and especially British jewelry, where local jurisdictions legally require precious metal items to feature assay office marks.
For instance, it is illegal to sell items described as being made of gold, silver, platinum, or palladium in the United Kingdom unless they feature an assay office mark, as per the Hallmarking Act of 1973.
Although there are assay offices in the United States, they primarily assist the U.S. government with minting coinage and do not have the same role as British assay offices. This is because, unlike the UK, hallmarking is not a legal requirement in the United States.
The best way to ensure your items’ purity and precious metal composition is to have them tested by a reputable buyer such as AU Precious Metals. We use state-of-the-art, non-destructive testing processes such as X-ray spectrometry to assess your items’ exact precious metal content and purity.
The following table lists common assay office marks:
| Country | Mark Description |
|---|---|
| Austria | A crown-shaped mark with the letter W |
| Cyprus | A rectangular octagon mark featuring an old sailboat, and a rectangular mark featuring a fish symbol and water lines |
| Czech Republic | A square mark with the letter P |
| Denmark | An oval mark featuring three towers |
| Finland | A crown inside a heart-shaped mark |
| Hungary | An oval shield mark with the letter H |
| Ireland | A rectangular octagon mark featuring an image of a sitting Hibernia, the personification of Ireland |
| Latvia | A woman’s head in profile with a circular mark for gold A woman’s head in profile with an oval mark for silver A woman’s head in profile with a diamond mark for platinum A woman’s head in profile with a rounded rectangular mark for palladium |
| Netherlands | A circular mark with the letters “NL ASSAY OFFICE” A circular mark with a horse’s head and “NL” |
| Norway | The standing lion of the Norwegian coat of arms in a circular mark |
| Poland | The Polish coat of arms in a circular mark |
| Sweden | The Tre Kronor (Three Crowns), a Swedish national emblem |
| Switzerland | A dog’s head in a polygonal mark |
| United Kingdom | A sideways anchor for the Birmingham office A castle for the Edinburgh office A leopard’s head for the London office A rose for the Sheffield office |
Date Letters
Date letters, symbolizing the year of hallmarking, are represented by a single letter inside an octagon. This letter indicates the year the item underwent purity testing, not the year of manufacture.
The use of date letters dates back to 1478 when London introduced it to regulate gold and silver items. Each year was assigned a unique letter in the alphabet, with modifications made every 25 years to prevent fraud.
Contact AU Precious Metals to Get Your Jewelry Tested
Do you have jewelry made of gold, silver, platinum, or any other precious metal? Contact AU Precious Metals today and schedule assaying of your items in person or via our mail-in program. Our friendly and professional staff will guide you through our process and help you determine the precise composition of your precious metal items.