Jewellery Jargon
Unlike diamonds & gemstones, where carat refers to the size of the stone, in precious metal terms Carat relates directly to the purity of a metal, relative to that in its natural state. For example, Gold in it's purest state as found from the earth is 24ct, whereas 9ct Gold features far less Gold content and more alloys mixed.
ALLOYS OF PRECIOUS METALS
Alloy
An alloy is a mixture of metals or a mixture of a metal with another element. In jewellery making precious metal alloys such as Sterling Silver which is an alloy of Silver contains 92.5% of Silver by weight and 7.5% of other metals usually copper. Alloys are made to provide better strength and workability by jewellery manufacturers as both Gold and Silver in their purest form are soft metals.
Assay
A scientifically accurate test carried out to determine the content and quality of a metal. In the UK assaying is conducted by industry appointed Assay Offices.
Assay Office Mark
An official physically endorsed stamp mark found on all assayed and hallmarked precious metal articles to authenticate that the particular article has been tested by that Assay Office. In the UK there are four Assay Offices: The Birmingham Assay Office, Edinburgh Assay Office, The Goldsmith’s Company Assay Office in London and Sheffield Assay Office each with their own unique mark.
Carat
Carat (CT) or Karat (KT) is a fractional measure of purity for Gold alloys.
Commemorative Marks
These are a series of special hallmarks which celebrate major historical events. Examples include the 1955 Coronation, 1977 Silver Jubilee, 2002 Golden Jubilee and most recent 2012 Diamond Jubilee.
Copper
A type of metal commonly used in a wide range of applications including electronics, building construction, automotive parts and of course jewellery. It is a soft, ductile and malleable metal and one of the very few occurring in nature that can be used directly in its original form. In jewellery making Copper is used in the alloy of Sterling Silver and Gold to provide strength and durability.
Date Letter
One of the hallmarks applied on a precious metal article to show the year in which it was hallmarked.
Gold
The godfather of all precious metals, Gold has a lustrous royal yellow colour and has been used for thousands of years. In its purest form it is highly valued as a form of currency, traded in investment bullion bars and coins and in jewellery where gold alloys are created. The natural properties of gold being a soft, ductile and malleable metal, makes it the perfect choice.
Millesimal Fineness Mark
This is a numerical mark expressed in parts per thousand usually three digits which indicates the type of precious metal and fineness quality. For Gold the marks are 375 for 9ct, 585 for 14ct, 750 for 18ct and 916 for 22ct. For Platinum it is 950. For Sterling Silver it is 925.
Platinum
Regarded as one of the most romantic metals and a contemporary favourite in the jewellery world, Platinum which has a striking silvery-white colour is the rarest and most expensive of the precious metals. It is a very strong metal resistant to corrosion and scratching in addition to being hypoallergenic. Platinum beautifully compliments Diamonds enhancing their wonderful sparkle and is the perfect metal choice found in the most elegant engagement and wedding rings.
Rhodium
A fellow member of the Platinum family Rhodium is a silvery-white coloured metal favoured in jewellery making for its hardness, durability and anti-tarnish properties. It is popularly used as a plating element to provide enhanced protection found in all precious metals but commonly White Gold and Sterling Silver jewellery.
Rose Gold
Considered as a dreamy metal owing to its beautiful pinkish rosy-red colour, Rose Gold is an alloy mixed with copper. The amount of copper added in the alloy will determine the overall colour tone.
Sterling Silver
A timeless classic and the world’s most popular precious metal found in jewellery and silverware. Sterling Silver is loved for its shimmering shine and reflective appearance in addition to being very affordable. It is an alloy mixed with 92.5% Silver by weight and 7.5% other metals usually copper. As pure Silver alone is soft but malleable these additional metals are mixed to provide better strength and durability.
Sponsor’s Mark
One of the hallmarks applied on a precious metal article which is a unique mark of the company or individual responsible for sending the article for hallmarking. Sponsors are usually manufacturers, wholesalers or retailers and are required to be approved by registering with the Assay Office.
Traditional Fineness Mark
This is an optional unique pictorial symbol denoting the type of precious metal the article is made of.
White Gold
A fashionable metal which has a white colour similar to Platinum, White Gold is an alloy mixed with white metals such as Nickel, Palladium and Silver making it one of the more durable and scratch-resistant. It is commonly plated with Rhodium which is another white metal to enhance the overall whiteness of the finished jewellery piece.
Yellow Gold
A timeless classic loved for its glittery yellow colours, Yellow Gold is an alloy mixed with copper and zinc. It is the most hypoallergenic of the three gold colour types. The amount of copper and zinc added in the alloy will determine the overall colour tone.