Likewise, 14 Karat gold is 58.5% pure (585 parts per thousand) and 18k gold is 75% pure. Jewellers in the UK are not allo to describe an item as solid gold unless it is hallmarked.

Gold is normally hallmarked i.e. Understanding some of the fundamentals about hallmarking and the tests commonly applied when valuing gold is useful; especially if you wish to sell gold either online or through a retail outlet. The UK is also a signatory to the international convention on hallmarks which means convention hallmarks are also recognised in the UK. Stamped to indicate the type of gold.

That's true enough but probably not good enough if you are going to understand the true value of your gold. You can get more information at the British Hallmarking Council website. For example, gold which contains 375 parts of gold per thousand is 37.5% pure and categorised as 9K Gold. The colour of gold has nothing to do with the quality and is the result of mixing the gold.

UK hallmarks are 375, 585, 750, 916, and 999.