It might be the smallest of details, but the hallmark is a vital finishing touch on any piece of precious jewellery. Seeing a little row of stamps or an engraved mark is your assurance that your new piece of jewellery is everything you expected.

What is a Hallmark?

Since 1973, any piece of silver jewellery with a metal weight of over 7.78g or gold jewellery weighing more than 1.0g must be hallmarked by law.

The hallmark records the percentage of real gold or silver in the metal which makes up your piece. Most jewellery is made from an alloy; pure gold and silver combined with other metals to achieve a desirable durability and colour.

At the Assay Office the percentage of pure precious metal in a piece is tested. If the minimum purity is achieved the piece is stamped or laser-engraved with a row of marks that certifies this; the hallmark. The word ‘assay’ is actually thought to come from an old French word essai, meaning trial.

Our Hallmarking Promises

Here at With Bling we take care to ensure our jewellery meets all UK hallmarking requirements, giving you complete confidence in the pieces you choose from us.

We also make sure all marks are placed on the back of your jewellery or on the earring post so they are not visible when worn. Hallmarks are designed to be unobtrusive, so you might need a magnifying glass or loupe to see the smallest marks.

Sterling Silver

Our pieces that contain silver are at 92.5% purity, which is the quality standard for silver jewellery. You will find a ‘925’ purity stamp on every piece of our silver jewellery, and a full hallmark on our heavier pieces over 7.78g such as statement earrings or hoops.

Solid Gold

Our solid gold pieces are either crafted from 10K or 14K solid gold. You will find a ‘10K’ or ‘14K’ stamp on every piece of our solid gold jewellery, and a ‘9K’ or ‘14K’ full hallmark on our heavier pieces over 1g.

What makes up a Hallmark?

A hallmark tells you more than metal purity alone. Take a closer look at the symbols and you can find out more about where and when your piece of jewellery was made.

There are three compulsory parts to any hallmark: the Sponsor’s Mark, Fineness Mark and Assay Office Mark. In addition to these compulsory marks, there are some other optional symbols your hallmark could contain. With Bling jewellery features four parts to the hallmark: the Sponsor’s Mark, Convention Mark, Fineness Mark and Assay Office Mark.

1. Sponsor's Mark

With Bling Sponsor's Mark

The Sponsor’s Mark (sometimes known as Maker’s Mark) identifies the company that made your jewellery. Each manufacturer has its own unique mark made up of initials inside a shaped frame. On With Bling pieces you will see ‘WB’ inside a oval.

2. Convention Mark

With Bling International Convention Mark

The Convention Mark allows jet-setting jewellery to be sold between some countries without the need for an additional assay process. Known as The Hallmarking Convention, ‘The Convention on the Control and Marking of Articles of Precious Metals’ is an international treaty that came into force in 1975. Applying the Convention Mark means the UK-applied hallmark is accepted for sale in contracting states, and is recognised as an indication of quality worldwide.

More information on Convention and its Hallmarks can be found here.

3. Fineness Mark

With Bling Finesse Mark

The Millennial Fineness Mark is the grade of purity written as parts per thousand. Taking 14K gold as an example, the jewellery is made up of 585 parts of pure gold out of 1000. The remaining 415 parts are other metals that the gold is alloyed with, which adds strength and makes it a more suitable material for jewellery. Therefore, our 14K gold jewellery that is over 1g will receive a ‘585’ hallmark.

4. Assay Office Mark

With Bling Assay Office Mark

There are four Assay Offices in the UK: Sheffield, Birmingham, London and Glasgow. Each one has a different stamp – their ‘town mark’ - which is included in the hallmark. In a With Bling hallmark you will see a leopard, which means that your piece was hallmarked in London.

5. Date Letter (Optional)

With Bling Date Letter

Date Letters: 2019 - 2024

If your hallmark contains a letter you can use this to find out exactly what year the piece was assayed. Running from A to Z, the letter changes every year on January 1st. As neighbouring letters ‘i’ and ‘j’ can look alike, one is usually skipped. When the alphabet has been exhausted a new cycle begins with a different typeface and sometimes case. Running from the year 2000 to 2024, the current date stamp features uppercase letters in a hexagon.

Since 1975 all assay offices have used the same date stamp design, so checking the year on a modern piece is straightforward. For vintage and antique pieces, a little more investigation is required. You will need to check the ‘town stamp’ to see which assay office marked the piece and then research their specific historic date letter designs.

You can see more of the Hallmarking process here.

Why does your 9K Jewellery have a 10K Stamp?

You may notice that some of our pieces have a 10K stamp but are described as or hallmarked with ‘375’ (9K). This is because With Bling jewellery is popular all over the world, and to conform with the metal purity standards of some other countries, we make our pieces in at least 10K gold. In the UK there is no specific hallmark for 10K, so although our 10K jewellery all have a 10K stamp, they are described as or hallmarked with ‘375’ (9K).

Exceeding the requirements for UK hallmarking is actually less expensive than making the same design in different purities for different countries, so we choose to make everything in 10K. And as always, we pass the savings on to you!

Karat or Carat - What’s the difference?

In the UK a carat is a unit of weight used to describe both gemstones and metal, usually abbreviated to ct – a 0.50ct diamond set in 9ct gold, for instance.

Worldwide, karat is more commonly used for metal. We think it helps differentiate between our gold and stone weights, so karat is what we use. When you see us refer to 9K, 10K or 14K gold, this is the same as 9ct, 10ct or 14ct.