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Jewellery Guides - Gold
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Gold is an element which bears the symbol Au, taken from the latin word ‘aurum’. Gold is a highly sought after precious metal, occurring as nuggets or grains in rocks.
The proportion, or purity of gold in jewellery is measured in terms of carat (or karat in the US or Canada), with pure gold equating to 24 carat gold or 99.9% gold. Pure gold is a soft, malleable metal and is therefore alloyed with other metals to add strength. The word ‘carat’ comes from the Greek word for ‘carob seed’, which were originally used as weights on precision scales in Oriental markets, owing to their reputation for having a uniform weight. Thus we have (most commonly) 24 carat gold (99.9% gold), 18 carat gold (75% gold), 14 carat gold (58.5%), 9 carat gold (37.5% gold).
By law in the UK, all gold over 1 gram in weight must be hallmarked or carry a stamp of purity, such as ‘375’ for 9ct gold or 585 for 14 carat gold etc. No stamps are required for gold under this weight. UK hallmarks are applied by 1 of 4 Assay Offices that test (and guarantee) the purity of the gold, and provide an assurance that the item conforms to legal standards. A UK hallmark, as of 1 January 1999, must consist of 3 symbols denoting the sponsor’s or maker’s mark, a metal and purity (fineness) mark and the Assay Office mark. The 4 UK Assay offices are: Birmingham, Edinburgh, London and Sheffield.
Rose gold is created by alloying yellow gold with copper and is sometimes referred to as pink gold or red gold. The higher the copper content, the stronger the red colouration. Rose gold commonly consists of 75% yellow gold combined with 25% copper, creating 18 carat rose gold. Occasionally, 4% silver is added with 21% copper.
White gold is an alloy of yellow gold and one silver/white metal such as palladium or nickel. The highest purity of white gold is typically 18 carat, consisting of gold and palladium, or gold and nickel, although occasionally silver or platinum is added. Rhodium plating maintains the lustre of the white gold.
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