As Treasure Hunters, we tend to find a LOT of items that are “Hallmarked”. In this article, we hope to give you a quick insight into what they are, what they represent and how to read them.
A hallmark is an official mark or series of marks struck on items made of metal, mostly to certify the content of valuable metals —such as platinum, gold, silver and in some nations, palladium. Hallmarks date back to the medieval period and the practice of applying them as a guarantee of the purity of the precious metal content.
Hallmarks can be applied in one of three ways. The traditional method of marking is by hand punches and is still the favoured method today. Press marking is an automated form of hallmarking and now, in the 21st century, marking by laser is also becoming more popular.
Components of a hallmark
The four components of a hallmark are –
- Sponsor or maker’s mark (the manufacturer)
- Assay office mark (where it was tested and certified)
- The date letter (when it was tested and certified)
- The standard mark (precious metal content)
Hallmark identification should answer four important questions – where; what; when; who.
A Sponsors or Makers Mark is the designer, manufacturing firm or representative symbol that is stamped into your precious metal – also called trademarks. This mark provides proof that your jewellery item was made by the designer or jewellery maker and is considered “signed”. All marks need to be registered by an Assay Office.
Assay Office Mark
The Assay Office Mark tells you where your item was tested for its purity. Although manufacturing of precious metals has existed for hundreds of years, it only started in the U.S. around 1840. So many older items in the U.S. will be stamped with European marks – so it’s important to be aware of them as well. Even in the U.S., it wasn’t until 1906, that the regulations around hallmarking went into effect.
This stamp will tell you the year the purity of the item was tested – not the year the item was manufactured. Be careful – it can be tricky. You will hardly ever find this on a delicate piece of jewellery because there is simply not enough room.
If you do find a date on your piece, it will not look like your typical date. The date will be in the form of a letter. In 1478, London introduced a practice of dating all gold and silver artefacts and had it managed by a governmental controlled body. To prevent fraud, every year was assigned a letter in the alphabet. Every 25 years they would then make modifications to the font or design around the letter to prevent confusion.
Other Marks Aside from gold, silver and platinum there are a lot of other hallmarks you will see stamped in the jewellery you’ll find that is meant to tell you about the item’s contents and purity.
- GF Gold Filled
- P Plum Gold (this shows the item is at least the amount in karats as shown on the stamp)
- KP Karat Plum (this means the item is at least the karat listed, but may be more pure)
- Pd Palladium
- PT Platinum
- PLAT Platinum
- Silver Stirling Silver
- SS Stainless Steel
- CW Carat Weight (typically will be an indicator of the gem or diamond weight)
- CZ Cubic Zirconia
- SOL Solitaire Diamond
- 4, 5, 6, 7, etc If a low number, it is typically an indicator of the ring size
Gold Stamps and What They Mean
Below are the most common GOLD stamps you’ll find on jewellery…
- 8K, 8ct or 333 (parts per 1000) or is 33.3% gold Usually European. Not recognised in USA. The lowest possible standard. Will tarnish sometimes
- 9K, 9ct or 375 (parts per 1000) or is 37.5% gold Mainly British Commonwealth countries. Not recognised in USA. (Hard wearing.)
- 10K, 10ct or 416 (parts per 1000) or is 41.6% gold Minimum USA standard. (Hard wearing.)
- 12K, 12ct or 500 (parts per 1000) or is 50% gold Usually old watch cases. (Rarely seen)
- 14K, 14ct or 585 (parts per 1000) or 58.5% gold Asian for overseas market. Common in USA. (Russian 584.)
- 15K, 15ct or 625 (parts per 1000) or 62.5 % gold British Commonwealth countries. Discontinued around 1935. (A good indicator that the piece is old.)
- 18K, 18ct or 750 (parts per 1000) or 75% gold. Most quality pieces are 18ct. Minimum gold standard for sale in Italy.
- 22K, 22ct or 916 (parts per 1000) or 91.6% gold Mainly Asia, Middle East. Very soft. (Very yellow)
- 24K, 24ct or 1000 (parts per 1000) or PURE gold (Too soft for most jewellery manufacture)