As England celebrates the coronation of King Charles III this weekend, the crowns will be the centre of attention. Combined, the three crowns used in the ceremony contain almost 6,000 gemstones — this graphic takes a look at their chemical compositions.
Diamond is commonly known to be the hardest material, but how do other minerals compare with each other? That’s the question the Mohs hardness scale, introduced by Friedrich Mohs in 1812, aims to answer. This graphic looks at his scale and where different minerals and other substances appear on it.
There are a wide range of gemstones used in jewellery, with each having its own characteristic colour – or, in some cases, a range of colours. The origin of these colours has a chemical basis, and the precise colour can vary depending on the chemical composition of the gemstone. Interestingly, many minerals are actually colourless in their pure form, and it is the inclusion of impurities in their structure which leads to their colouration.
