Precious Metals

Hallmarks & Precious Metals

Hallmarking began somewhere back in the thirteenth century most likely in France.  Its purpose was to test coins made of silver and gold so that the correct amount of precious metal was actually in the item.  It was the original consumer protection law.

In England in 1327 it became law that if you were selling an item made of precious metal it had to be tested.  Manufacturers were compelled to take their articles to the hall where the Assay Master would test the precious metal content.  Once it passed the test then he stamped the item with marks indicating the fineness or content of the precious metal and eventually other stamps were added such as a date, maker and the assay office mark. So that is where the term Hallmarking came from.

Below is a list of some of the symbols you may see in your jewellery and what thet relate to.

 The tests are carried out by an assay office, of which there are four in the UK , London , Birmingham , Sheffield and Edinburgh. These are the symbols represented in the hallmarks for the relevant assay office in the UK.

9ct Gold

This is available in a few colours, most popularly yellow and white. This is a less expensive precious metal than 18 carat gold. It contains 37.5% gold and is alloyed with other metals to increase the hardness, durability and colour. It is represented by the figures 375 in hallmarks.

18ct Gold

This is one of the most popular precious metals for high quality jewellery. It contains 75% pure gold and is represented by the figure 750 on hallmarks. It is available in both yellow and white gold. Because of the high content of gold, 18 carat white gold would naturally appear more of a straw white colour. It is for this reason that  white gold jewellery sold is rhodium plated to finish the item with a very white, hard and durable coat. This hard finish will, over a long period,  eventually wear, especially on rings worn on a daily basis. As with any metal though, scratches are unavoidable.  It can, however, easily be re-applied at any time by a jeweller. The ring is normally polished, and then rhodium plated and will be returned to as new condition.

Platinum

Most platinum jewellery sold in the UK is 95% pure. It will thus have hallmarks with the figures 950, denoting the purity It is naturally a hypoallergenic metal and always remains white. A ring in platinum will be approximately 40% heavier than the equivalent ring in 18ct gold. Due to its hardness platinum will always provide excellent protection for a diamond.

Precious Metal Information

Yellow Gold

Gold itself is a yellow metallic element but, in its pure form, it is too soft to be used for general jewellery purposes The yellow colour of gold is caused by gold absorbing violet and blue light, but reflecting yellow and red light. It is usual for gold to be mixed with other metals to produce an alloy, which is simply a mixture of two or more metals. Throughout history, most people have preferred the colour of gold jewellery to remain close to that of pure gold itself, and so most jewellery has historically been made using yellow gold alloys. Other metals mixed with gold to produce alloys include copper and silver, which are the common components of most yellow gold alloys.

White Gold

There is no such thing as white gold. There are however gold alloys which appear white, silvery, or grey. White gold alloys became fashionable in the 1920's, mainly as a substitute for platinum, which had itself recently become fashionable. Simply mixing a white and a yellow metal together does not just produce a pale yellow colour, alloying produces a difference in the atomic structure which alters the reflectivity of light of different wave lengths. The commonest metal which causes a significant bleaching effect in gold is nickel, however it sometimes causes an allergic reaction when worn in contact with the skin. In recent years E.C. Regulations covering the use of nickel in jewellery have been implemented, and all or most new jewellery manufactured now has to be nickel-free, or at least "nickel-safe". After a piece of white gold jewellery has been made it still has a slight tinge of yellow to it so it has to be Rhodium Plated which gives it its bright white look, this process has to be repeated every year to eighteen months.

Platinum