Closing down - 30% off everything - discount applied at checkout


Your Cart is Empty

The Ultimate Guide to Jewellery Hallmarks - What Do They Mean & Why Do We Use Them?

27 March 2022 6 min read

Have you ever noticed the tiny markings on a piece of fine jewellery and wondered what they mean?

Well…as it turns out…they’re actually pretty important.

These miniscule markings are hallmarks, designed to let you know that the piece of jewellery you are buying is genuine. Without them, we’d be clueless when it comes to figuring out what our jewellery is worth.

Why hallmarking?

Precious metals, such as gold and silver, in their purest form are too soft to be used in jewellery. So, to make them strong enough and workable enough to be turned into wearable pieces, they need to be alloyed with a base metal. Usually, this is copper. But other metals can be used. This leaves you with a more durable metal alloy, which still retains the beauty of the precious metal.

More base metal in the alloy makes the piece harder, but also more prone to corrosion. Therefore, jewellery with a higher percentage of precious metal in the alloy is longer lasting and, unsurprisingly, more valuable.

The alloys are formed in such a way that even most experts can’t tell the level of quality and fineness of the metal, just by holding or looking at it.

Why hallmarks are important

Before hallmarking was introduced, some traders realised they could turn a better profit by reducing the precious metal content of the alloy. In some cases this meant jewellery formed of mostly base metal, with a thin plating of precious metal which, as we know, won’t last.

Hence the need for compulsory, independent testing was recognised and the process of assaying and hallmarking established.

Hallmarking helps us set apart the fine and demi-fine jewellery from costume jewellery.

UK law requires that gold, silver, platinum and palladium jewellery contain a minimum amount of pure metal, in order to be classified as ‘precious’. This is also known as ‘fineness’.

A hallmark is used to show buyers that a piece of jewellery meets this minimum standard.

Since 2009, it’s illegal to sell or describe any item as one of these four precious metals unless it is hallmarked.

The history of hallmarking

The assaying and hallmarking of precious metals began in 1300, thanks to a statute of King Edward I. The goal of said statute was to put an end to unscrupulous manufacturers passing off poor quality metals as precious (a common practice), protecting consumers against fraud and legitimate jewellery traders from unfair competition.

Quality testing

The Wardens of the Company of Goldsmiths in London were tasked with the role of assaying gold and silver at workshops across the City. Assayers would mark each article with a leopard’s head symbol (the current mark of the London Assay Office). At first, only silver was marked, with the marking of gold introduced sometime later. This assured buyers and collectors that the jewellery had been tested.

Tracing the origin

Later, in 1363, the maker’s mark was created to help trace the origin of each piece. The maker’s mark tells us who made the article. Initially, images were used but, as public literacy rates improved, surrounded initials became the more common mark.

The Wardens set up the first formal assay office base in Goldsmith’s Hall in 1478. They also introduced the use of date letter marks, helping buyers identify the assayer of their piece and making assayers accountable for their work. The Edinburgh Assay Office can be traced back to the mid 15th century.

In the late 18th century, two more assay offices were established by the Hallmarking Act 1773 - Birmingham and Sheffield (all illi jewellery is hallmarked by the Sheffield Assay Office). Other UK offices have been established but have since closed.

What does ‘assay’ mean?

Assaying is the testing and analysing of a piece of jewellery to determine its purity. Or, put another way, how much of the piece’s metal alloy is a precious metal. This is measured in parts per thousand.

Scraping samples

Historically, assay offices would scrape or cut tiny amounts of metal from each item of jewellery. These samples would then be tested. Gold samples were tested using a process known as cupellation, which involves treating the metal under high temperatures to separate precious metal from base metal. Silver samples were tested using a method known as titration - a chemical process that tests the sample’s reaction with nitric acid, using additional substances as indicators.

As a result, manufacturers would typically send in pieces that were unfinished, meaning marks left by scraping samples could be easily removed during the finishing process.

X-ray technology

In the late 1990s, UK assay offices began moving away from these methods towards a new technique - X-ray fluorescence. An X-ray beam is emitted onto a flat surface of the piece. The beam penetrates the surface of the material and “excites” the atoms in the alloy. The intensity of the energy emitted by these “excited” atoms is then measured and analysed, providing an accurate reading of the percentage of each element present in the piece.

Using this method eliminates the need for scraping (meaning jewellery can be sent in its finished form) and is more eco friendly as it doesn’t require high temperatures for testing.

High standards

Standards are strict, with no negative tolerance allowed. That means that if, to be classed as ‘gold jewellery’, the amount of pure gold in the alloy must be at least 375 parts per thousand, a piece with 374 parts per thousand won’t make the grade.

Once each piece has been independently tested, it is hallmarked using either a stamp or a laser. This hallmark proves that it can be legally sold as genuine precious metal.

The UK has four assay offices - London, Birmingham, Sheffield and Edinburgh. Each office has a recognisable mark added to each hallmark so you know where it was assayed.

  • London - Leopard’s head
  • Birmingham - Anchor
  • Sheffield - Tudor rose (prior to 1974, it was a Crown)
  • Edinburgh - Castle

What is a hallmark?

A hallmark is actually made up of at least three different marks, typically displayed left to right in a horizontal line on an inconspicuous area of the jewellery (such as the inside of a ring band), no more than 1.5mm in height.

    1. The sponsor’s mark, also known as the ‘maker’s mark’

This is the registered mark of the company who made the piece. Every jewellery manufacturer has their own unique mark. Ours is our name - ‘illi’, surrounded by a rectangular shield.

    1. Fineness mark

This mark lets you know the degree of precious metal content in the piece, measured in parts per thousand. The marks vary depending on the type of metal, as well as the minimum standard of alloy content.

Metal Purity Precious Metal (parts per thousand) Purity Precious Metal (parts per thousand) Purity Precious Metal (parts per thousand) Purity Precious Metal (parts per thousand)
Gold 9ct 375 14ct 585 18ct 750 22ct 916
Silver Sterling 925 Britannia 958 - 999 - -
Platinum - 850 - 900 - 950 - 999
Palladium - 500 - 950 - 999 - -

    1. Assay office mark

This mark tells you which of the UK’s four assay offices tested and hallmarked the piece. A leopard’s head for London, an anchor for Birmingham, a Tudor rose for Sheffield and a castle for Edinburgh.

These three marks are compulsory on all jewellery sold as containing precious metal.


There are other, optional marks that can be found on some jewellery. Some pieces will include traditional fineness symbols that are pictorial rather than numerical like the compulsory fineness mark. And others, if made for or during a special event such as the Queen’s Jubilee, may have a commemorative mark.

A common additional mark found on fine jewellery is date letter marking (made optional in 1999), which displays a letter of the alphabet for each year. This tells us the year the piece was assayed. The letter used each year is the same across all four assay offices (since the Hallmarking Act 1973 made it mandatory). At the beginning of the year, a new date stamp is created, which is then destroyed at the end of the year. When all the letters have been used, the assay offices will change the font and start again at the beginning of the alphabet.

In 1972, the UK became a signatory to the International Convention of Hallmarks. The convention helps safeguard the trade of jewellery internationally. This is done using common control marks, which are recognised by all members of the convention. The control marks indicate the fineness of each piece. Currently, there are 20 member countries - Austria, The Netherlands, Cyprus, Norway, Czech Republic, Poland, Denmark, Portugal, Finland, Slovakia, Slovenia, Hungary, Croatia, Ireland, Switzerland, Sweden, Israel, Latvia, Lithuania and the UK.

Most hallmarks can only be viewed properly using a loupe, which is a special magnifier used by jewellers and jewellery experts.

As well as making sure jewellery is hallmarked, dealers are required by law to exhibit a notice detailing their hallmarks. You can view ours here.

Every single piece of illi jewellery is hallmarked so you can trace its story and quality. We use 100 percent recycled precious metals in our jewellery and we pride ourselves on creating beautiful, sustainable fine jewellery that can be treasured for a lifetime.

Shop recycled gold and silver jewellery from our collection and sign up to our mailing list to get 10 percent off your first order.