The chemical symbol for gold is Au, from the Latin aurum, which means 'shining dawn'. Aurora was the Roman goddess of dawn which links to the warm, yellow colour of gold. Gold and Copper are the only two non white coloured metals.
Gold and copper were the first metals to be discovered by man, around 5000BC, and together with silver these three metals are found in the metallic state in the earth's crust. Gold is still mined in its metallic form in over 60 countries around the world.
Gold is referred to as a precious and a noble metal. Gold has an excellent chemical stability with a high resistance to corrosion and oxidation. However, this is just one of the many properties that gold possesses, which when considered in combination with each other have led to a number of exciting and often unique industrial applications.
The purity of gold is measured in Carats. A Carat was originally a unit of mass (weight) based on the Carob seed or bean which was used by ancient merchants in the Middle East. The Carat is still used for the weight of gem stones where 1 carat = 200mg. For gold is is used to measure the purity where pure gold is 24 carats. The following table shows the range from pure gold at 24 Carats to less pure at 9 Carats.
In Europe 18 and 14 carat alloys are most commonly used in jewellery, however 9 carat is popular in Britain.
In many countries the law requires that every item of gold jewellery is clearly stamped with its caratage. Jewellery in many countries is stamped or hallmarked with its caratage. The hallmarking system was developed in London in the 14th century at Goldsmiths' Hall.
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