GUARANTEEING THE QUALITY OF PRECIOUS METALS SINCE 1327
The purpose of this document is to give practical guidance in relation to Hallmarking matters. The UK Assay Offices are happy to answer questions arising from this information.
Selling Precious Metal Jewellery in the UK
Traders who wish to sell precious metal jewellery, ie Platinum, Gold or Silver in the UK must follow the rules laid out by law in the Hallmarking Act 1973.
If these rules are not followed Trading Standards Officers have the right to seize goods immediately and the seller is committing an illegal act.
Why is the Hallmark important?
For the manufacture of jewellery and silverware precious metals are not used in their purest forms. Instead they are mixed with other metals like zinc and copper, known as base metals.
The resulting mixture is what is called, an alloy. This is done to give greater strength, durability or a particular colour to the metal.
It is not possible to discern by sight or by touch how much precious metal, if any, is present in an alloy. It is therefore a legal requirement, in the UK, to hallmark all articles consisting
of gold, silver or platinum (subject to certain exemptions) if they are to be described as such.
Precious metal is expensive. If you buy an item which contains less precious metal than it should, then you are being cheated.
The hallmark is your guarantee so you know what you are buying.
It is an offence under the UK Hallmarking Act 1973 for any person in the course of trade or business to:
• Describe an un-hallmarked article as being wholly or partly made of gold, silver or platinum.
• Supply or offer to supply un-hallmarked articles to which such a description is applied.
How is the precious metal content of an alloy measured?
Gold alloys are graded by carat. The higher the carat, the greater the proportion of gold is in the alloy, up to a maximum of 24 carat (pure gold).
The diagrams above illustrate the percentage of precious metal that should be present in some of the more common precious metal alloys used in jewellery.
In a hallmark the precious content is expressed in parts per thousand, e.g. 375, 750, 925 etc
What needs to be hallmarked?
Any article described as being wholly or partly made of gold, silver or platinum that is not covered under exempt articles.
Articles below a certain weight are exempt from hallmarking. The exemption weight is based on the weight of the precious metal content only, excluding, for example,
weight of diamonds, stones etc., except in the case of articles consisting of precious metal and base metal in which case the exemption weight is based on the total metal weight:
• Gold 1.0 grams
• Silver 7.78 grams
• Platinum 0.5 grams
What does a Hallmark look like?
A hallmark can only be applied by an independent Assay Office.
A Hallmark is made up of 3 compulsory symbols:
1. The Sponsor’s or Maker’s Mark
This indicates the maker or sponsor of the article. In the UK this mark consists of at least two letters within a shield. No two marks are the same.
2. Metal and fineness (purity) Mark
Indicates the precious metal content of the article and that it is not less than the fineness of the article indicated. The fineness is indicated by a millesimal number and the metal type is indicated by the shape of the surround.
3. Assay Office Mark
Indicates the particular Assay Office at which the article was tested and marked. There are now 4 Assay Offices in the UK - London, Edinburgh, Birmingham and Sheffield.
Sponsors or Makers Mark
Metal and Fineness (purity) Mark*
Assay Office Mark
* The Hallmark guarantees that the purity of the metal is at least that indicated by the Fineness Number.
There are also a range of optional symbols that can be applied alongside the Hallmark. These are:
Traditional Fineness Symbols
Prior to 1999, silver and platinum fineness were indicated by symbols.
The Date Mark
The date letter is optional in addition to the compulsory marks. The date letter changes once a year on January 1st.
For earlier date letters check with the relevant Assay Office. Birmingham www.theassayoffice.co.uk, Edinburgh etc
The Common Control Mark
The UK has been a signatory to the international Convention on Hallmarks since 1972. This means that UK Assay Offices can strike the Convention Hallmark which will then
be recognised by all member countries in the International Convention. Conversely, Convention Hallmarks from other member countries are legally recognised in the UK.
Articles bearing the Convention Hallmark do not have to be re-hallmarked in the UK. The outline of the mark varies according to the type of Precious Metal.
Three things to remember
Remember that if the mark does not have at least these three symbols then it is not a hallmark. In many cases the manufacturer may stamp a number inside to
state the purity. This is not a hallmark.
Look for a statement in the item description that the item is hallmarked. Don’t be afraid to ask the seller if their products are hallmarked.
If you purchase jewellery without a hallmark there is no guarantee that what you have purchased contains any precious metal at all.
If you have any queries about hallmarks, you can contact any of the Assay Office of Great Britain:
London EC2V 8AQ
Tel: 020 7606 8971 Fax: 020 7814 9353
Birmingham Assay Office
PO Box 151
Birmingham B3 1SB
Tel: 0121 236 6951 Fax: 0121 236 9032
Sheffield Assay Office
Beulah Road, Hillsborough
Sheffield S6 2AN
Tel: 0114 231 2121 Fax: 0114 233 9079
Edinburgh Assay Office
24 Broughton Street
Edinburgh EH1 3RH
Tel: 0131 556 1144 Fax: 0131 556 1177
GUARANTEEING THE QUALITY OF PRECIOUS METALS SINCE 1327
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TROY OUNCE DEFINITION
1 Troy Ounce = 31.1035 grams
1 Ounce pure Gold = 31.1 grams 24 ct (0.9999%)
1 Ounce (1 Troy) 9ct gold bracelet weighing 31.1gms
contains (9/24)*31.1 = 11.66gms pure gold
Therefore (30.1 - 11.66) = 19.44 grams in every Troy Ounce is not gold
Gold Content by see-search.com
GOLD Parts/1000 Gold Content / Troy oz
9ct 375 11.66 gms
14ct 585 18.14 gms
18ct 750 23.33 gms
22ct 916 28.51 gms
99% pure 990 30.79 gms
99.9% pure 999 31.07 gms
24ct 100% 1000 31.104 gms
CHAIN LENGTHS by see-search.com
Inch cm Comment
16 41 Short Chain for Pendants
18 46 Standard Ladies, Small Gents
20 51 Long Ladies, Standard Gents
22 56 Long Pendant and Lockets
24 61 Long
28 71 Very Long
30 76 Extra Long
RING SIZES by see-search.com
UK mm Dia mm Circ US
A 11,5 36,25 0.5
B 12,3 38,64 1
C 12,7 39,9 1.5
D 13,1 41,15 2
E 13,5 42,41 2.5
F 13,9 43,67 3
G 14,3 44,92 3.25
H 14,7 46,18 3.75
I 15,1 47,44 4.25
J 5,5 48,69 4.75
K 5,9 49,95 5.25
L 16,3 51,24 5.75
M 16,7 52,46 6.25
N 17,1 53,72 6.75
O 17,5 54,98 7
P 17,9 56,23 7.5
Q 18,3 57,49 8
R 18,7 58,75 8.5
S 19,1 60,0 9
T 19,5 61,26 9.5
U 19,9 62,52 10
V 20,3 63,77 10.5
W 20,7 65,0 11
X 21,1 66,29 11.5
Y 21,5 67,51 12
Z 21,9 68,77 12.5