The talk took place on 9 th October 2018 at the Barn. Andrew Waite, the proprietor of Festoon UK, spoke to our group about the properties of amber two or three years ago and returned in October to talk about hall marking.
Over 700 years ago, as an old form of consumer protection, jewellers and precious metal workers marked their work with personal stamps but in 1773 King Edward 1 st introduced the first essay office. There are now four in Britain but several others around the world.
Birmingham, has an assay office mark of an anchor, Sheffield uses a rose, London a lion or leopard’s head and Edinburgh a castle.
Along with the maker’s mark, the assay mark, date mark and sponsor’s mark may be a number signifying the parts per thousand of silver, gold or platinum.
Sterling silver has to contain 92.5% precious metal and includes a hard metal, such as nickel, to make it more durable. Britannic silver contains 958 parts to 1,000. Gold is measured in karats as follows;
375 = 9 karat
585 = 14
750 = 18
916 = 22
99 = 24
Platinum has to contain 850 – 999 (parts out of a thousand).
Testing is done in a variety of ways. It may be done simply by using nitric acid or by using an XRF machine, which can measure the percentage of precious metal. Plasma optical machines are used for testing platinum.
Gold and silver are not magnetic so you can always try a simple test yourselves! Beware though for ‘all that glisters is not gold’. (1596 edition of The Merchant of Venice). Jewellers can of course send your items of to an assay office for verification. Since the Hallmarking Act of 2007 it is illegal to sell items as gold, silver or platinum unless they bear a hallmark.
We also learned about plating and gilding and, to whet our appetites for the next talk in the series, something about gemstones, which Andrew sources from places such as Australia, Brazil and Mexico. His jewellery was on sale at the end of the talk. For more information go to http://theassayoffice.co.uk/heritagehub/date-letters and Andrew’s website www.festoonuk.com
On 13th November, at 2 o’clock in the Church Barn, Kevin Varty will be telling stories about Joyce Grenfell in his talk entitled ‘Dancing Bust to Bust’. Our meetings are open to all. Come and join us!