Why weight matters to a UK hallmark
In the United Kingdom, section 1 of the Hallmarking Act 1973 makes it an offence, in the course of a trade or business, to describe an unhallmarked article as being made of gold, silver, platinum or palladium, or to supply one so described. Section 1(3) disapplies that for any article within Part II of Schedule 1, the list of exempted articles. Some exemptions are by type, such as coins and articles for medical or scientific use. Four are by weight, and they are the ones people mean when they ask whether a light ring or a pair of studs needs a hallmark.
The weight exemptions are paragraphs 12A to 12D. For articles made on or after 1 January 2008, they are the rules that apply. Older paragraphs, 12 and 14A, still sit in the schedule but apply only to articles made before that date.
The four weights
Silver: an article containing silver of minimum fineness, in which the total weight of the metal is less than 7.78 grams (paragraph 12A). Gold: less than 1 gram (12B). Platinum: less than 0.5 gram (12C). Palladium: less than 1 gram (12D).
Each is “less than”, so an article at exactly the line is not under it. A silver chain of 7.78 grams is not exempt by weight; one of 7.77 grams can be. The calculator treats the line as strict for that reason.
Mixed-metal articles
An article often contains more than one precious metal: a gold ring with a platinum setting, a silver pendant with gold detail. The schedule deals with this by excluding some combinations from each paragraph. Paragraph 12A, for silver, does not apply if the article also contains gold, platinum or palladium of minimum fineness. Paragraph 12B, for gold, does not apply if it also contains platinum. Paragraph 12D, for palladium, does not apply if it also contains gold or platinum. Paragraph 12C, for platinum, has no such exclusion.
Read together, those exclusions leave exactly one paragraph for any combination. If the article contains any platinum, the platinum line of 0.5 gram applies. Otherwise, if it contains gold, the 1 gram line applies. Otherwise, palladium’s 1 gram line. Only an all-silver article gets the 7.78 gram line. So a silver pendant with a small gold detail is tested against 1 gram, not 7.78, and the calculator shows which paragraph it used.
The other conditions
Weight is not the only test. Every paragraph requires the precious metal to be of minimum fineness, which section 22 of the Act sets at 375 for gold, 800 for silver, 850 for platinum and 500 for palladium, parts per thousand. Each fails if the article contains any precious metal below that fineness. Each also fails if the article contains materials other than precious metal, unless it meets the hallmarking conditions in Part 3 of Schedule 2 — the rules on what non-metal parts an article may have and still be hallmarked. And paragraph 14AA takes an article out of all of them if precious-metal solder below the standard an assay office would require has been used.
The weight is “the total weight of the metal”. The calculator asks for the total weight of the precious metal in the article and compares it with the line. It does not assess the other conditions, which depend on how the article is made.
What an exemption does and does not mean
An exemption means the article may be described as gold, silver, platinum or palladium in UK trade without a hallmark. It does not stop the article being hallmarked: makers and sellers can still send light articles to an assay office, and many do. Nor does it say anything about the article’s fineness beyond the minimum the paragraph requires. Separately, under section 1(4A) to (4D) of the Act, where a description of fineness is advertising or a commercial practice and is false other than by understating it, it is treated as misleading under consumer protection law.
The UK assay offices — London, Birmingham, Sheffield and Edinburgh — are the bodies that test and mark articles, and the right place to confirm how a particular piece would be treated. The UK assay office marks page shows each office’s town mark.