What is Hallmarking?
A silver bracelet from 1977 , showing London Hallmarks
History: -
To start this discussion, we first need to hop across to the UK. Which is where the term Hallmark comes from. For hundreds of years, since 1363 it has been a legal requirement in the UK for gold and silver to be hallmarked. This means the item is tested for purity and stamped using steel punches, with the appropriate marks to indicate its metal purity and origin. Initially, this was done at Goldsmiths Hall in London. Hence the term Hall – mark, ie Hallmark. Also known as “Assaying” This is still a legal requirement In the UK and there are currently five Assay Offices. London, Sheffield, Birmingham, Edinburgh (Scotland), And Dublin (Ireland).
When a jeweler, makes something or buys an unmarked wholesale item., it is sent to the assay office where it is tested (typically Using state-of-the-art X-ray machines). The metal must meet certain legal minimum standards. It can then be marked accordingly. Typically, a Hallmark will include with the sponsor’s mark, in my case a registered mark DW for Dave Wilson. Note that it’s called the sponsor’s mark, (not the makers' mark) as it’s the person who is paying for the hallmarking. It’s a common misconception that this is the person who made the item, but not necessarily. If I buy wholesale items, that are unmarked, I am obliged to send them for testing and hallmarking. They will ultimately have my DW mark, but I have not necessarily made them, I have simply paid (or sponsored) the hallmarking. Hence, with commercial mass-produced jewelry, the sponsor’s mark is often simply the retailer. For example, you may see genuine Tiffy & Co items hallmarked with T & Co, which is the company, not any specific individual in the factory, who may have made it.
There are various traditional marks to indicate the metal such as the Lion for sterling silver, the Crown for gold, and a mark for the Assay office who tested it. There may also be a letter that corresponds to the date. (optional now). Items imported into the UK must also be hallmarked and will have slightly different marks indicating they are imported.
UK (Scotland) Gold hallmarks, note the Crown indicating Gold
and the 375 indicating the purity.
The bust on the right is King Charles,
shown to mark his coronation year in 2023
It’s important to realize that in the UK this testing and marking is done completely independently under very strictly controlled conditions. Items found to be sub-standard will be rejected. Hence the UK offers one of the most accurate and reliable systems in the world and one of the best guarantees of purity and authenticity.
UK Carats
In the UK (and many other countries) Gold purity is referred to in Carats. Which means parts per 24. The most common being 9ct, with 18ct, and 22ct sometimes used. 24 Carat would be pure gold and too soft for jewelry. Pure gold is only seen as bullion coins and bars.
USA Karats
The USA also uses the carat system. But in the USA, it is written with a capital K, KARAT instead of the British Carat. This is simply to distinguish between Carats (metal purity), and Carats (Diamond weight). Both terms are spelled the same in the UK which often confuses. Hence in the USA Karat refers to metal purity and Carat only refers to gemstone weight. UK 18ct, USA 18K
Note about 9ct Gold
Whilst 9ct 375 gold jewelry is very prominent in the UK, accounting for the vast majority of retail jewelry, it is much less common elsewhere. In the USA 9ct is not officially recognised as gold. At just 37.5% gold the greater portion of the alloy isn’t actually gold, it is made up of other metals such as silver and copper. Typically it wil lhave more silver content than gold. Hence why many countries including the USA don’t describe this as gold. In the USA jewelry typically begins at 14K 583, which contains a much higher proportion gold.
Millesimal mark.
In more recent times, the Carat system has been supplemented by the millesimal mark. Instead of parts per 24, the purity is now represented as a three-digit number of parts per thousand. For example, 9ct gold, (9 parts per 24), is also identified as 375, meaning 375 parts per thousand, or 37.5% pure gold. Unless it meets this minimum purity, it cannot be marked as such by the Assay Office. Likewise, Sterling Silver is typically referred to as 925. This system has now been adopted by many countries in Europe. The number is shown in scales and referred to as the “Common Control mark”. And is used alongside the countries own specific marks. Globally this number system has also been widely adopted as a simple way to indicate the purity of precious metals.
The biggest difference in the USA is that there is no legal requirement for hallmarking and there are no official Assay offices to test and hallmark. It is therefore down to the individual manufacturer or retailer to mark the metal accordingly. (Hopefully accurately and honestly). Either using the Karat standard, or the millesimal mark. This can be done by use of steel punches.
Pepetools Hallmarkig punches.
Pepetools punches.
To assist in marking your jewelry, Pepetools have created a range of high-quality steel punches, featuring a range of precious and non-precious metal standards. Incluing some very hard to find punches for metals like Gold Filled and Copper.
Punches Available
- .925 (Sterling Silver)
- .999 (Fine Silver)
- .935 (Argentium Silver)
- 10K (10 Karat Gold)
- 14K (14 Karat Gold)
- 18K (18 Karat Gold)
- 22K (22 Karat Gold)
- STERLING (Sterling Silver)
- G.F. (Gold-Filled)
- CU (Copper)
- COIN
- PT (Platinum)
- PD (Palladium)
Note Cu is the chemical symbol for copper which has the Latin name Cuprum
Pepetools 18k punch for gold.
note when looking at the punch end on, the 18k is mirrored.
Tips on using marking punches.
When marking your jewelry, you only really get one shot. If the punch doesn’t mark properly or is misaligned, it is difficult to correct without polishing it out and starting again. So, the first and most important tip is to practice, ideally with a similar metal, but thin brass or copper sheet is a good medium to practice on.
Anneal.
If it is possible, anneal your metal before marking it, as this will soften the metal and help get a cleaner and deeper impression. To anneal most silver and gold alloys, heat to a deep cherry red (in the dark), hold at that temp for a few seconds, allow it to air cool to black heat (no longer glowing), then quench in water.
Work flat if you can.
if you are making a ring or a bangle from a strip, it’s easier to mark it flat before bending it into a shape. Punching can sometimes mark the underside of the metal, so it’s best to do this before final polishing, if possible. Be aware that there may be some small touch up required after marking.
Your metal also needs to be supported on a solid sturdy base. A Pepetools bench block is ideal for this purpose, giving a smooth flat surface, with the weight and resistance needed. Pepetools offer a range of hardened steel bench blocks, in different sizes, giving a solid smooth surface. Additionally paper parcel tape can be used on the block (or the underside of the piece) to further help reduce any marking.
Pepetools 2Lb Brass mallet. Essential for use with hardened steel punches.
Use a brass mallet. Important !
Marking requires a firm blow. However, as the steel punches are hardened steel it is preferable to avoid striking them with steel hammers, as this could case the hard punches to shatter. Pepetools supply a 2lb brass mallet, perfect for use with punches. This gives the weight needed to strike firmly, but the soft brass surface will not damage the punches.
Just enough force.
This is where the practice comes in. It is important to get a feel for how much force is required to get a good crisp impression. Too much force may cause unnecessary deformation of the piece or marking on the underside. Conversely, not enough force and the impression may be very feint or incomplete. So, use just enough force to get a good impression, ideally with a single strike.
Alignment,
Note that the Pepetools punches are square in section, this makes them easy to align, as the lettering is parallel to the front face. Ensure you know which way round it is facing to avoid punching the numbers upside down. Tip:- if the metal is polished, you will be able to see the reflection of the punch in the metals surface.
Align the punch with the centre line of the gold and keep the front edge parallel and square to the edge of the gold.
It is also vital to hold the punch vertical to the surface in all directions. Having the punch tilted, may result in only a partial impression, as only one side of the punch is impacting the gold.
Hold the punch vertical at 90° Degrees to the metal.
Ideally, you should only need to hit the punch once. Repeated attempts can cause multiple impressions and ghosting of the numbers. If you feel you do need several blows, it is vital that the punch remains in the same position and does not lift off in between strikes.
Incomplete strike.
May be due to insufficient force, or the punch not being perpendicular.
If you do lift the punch and realize that the impression isn’t complete, you can try to remedy this as follows. Holding the punch gently at your fingertips, slide it over the piece until it “drops" into the impression. This requires a very gentle touch, but you can usually feel when the punch has engaged with the original impression. Hold it firmly and strike again harder than the first time. It's not easy, but it is sometimes possible to re-strike in the same spot. Failing that, the impression must be sanded and polished out, or otherwise covered up with texturing or engraving.
Rock and roll.
Once you’ve got the right pressure you should be able to strike the punch just once. But with large punches such as STERLING, it may require a couple of strikes to fully complete the impression. Having stressed the importance of keeping the punch vertical, A great tip with larger punches is to tilt the punch slightly to the left and strike, then roll it a few degrees over to the right and strike again. This ensures both sides of the punch are fully impressed. You mustn't lift the punch in between strikes., simply tilt it on the spot, without shifting its placement. This takes practice, so try the technique on some scrap first. This technique is also used by people working with fancy logo punches or large letter punches. By tilting and rolling the punch around you ensure a full impression.
Rocking the punch from side to side as you strike, to get a fuller impression.
Marking your own ingots.
When I have a lot of scrap silver or gold left over from a job. I like to melt it down and cast it into little bars for later processing in the Pepetools mill. To identify what the metal is, I like to use punches to mark the ingots accordingly. They also make nice little gifts for my friends or to return leftover sentimental metal to the customer after a melt-and-make job.
Tip:- Mark your solder strips.
This is the best tip of all. If you use a strip, sheet or paillon solder, simply stamp it with the appropriate punch, I also use letter punches E M H for easy, medium and hard solders. If you use solder wire, simply mark a small metal tag and attach it to your wire.
Additional resources.
Pepetools have also created a superb Blog article about how to identify and read silver hallmarks and how to test silver and gold.. Check that out here....
