Understanding the Use of 9ct versus 18ct Gold
If everything else is equal, such as weight, the higher the carat number is, the more expensive the gold will be. This sometimes leads into questions as to why a jeweller might use18ct not 22ct/24ct and why on some 18ct pieces, there might be fittings of 9ct. This is easy to explain! Gold is a very soft metal in its natural near 100% pure form (24ct). In fact, it’s so soft that it’s often impractical to make jewellery out of it. Other metals need to be added for strength. Most jewellers consider 18ct to be the highest purity level that is a compromise between getting as much gold in as possible while giving the item enough strength so as to offer day-to-day robustness and longer-lasting durability. That’s why 18ct is often used as an international standard. However, even though 18ct has strength, the metal might still not be quite hard enough to cope with daily use stresses in certain situations. Let’s take a hypothetical example – a brooch with a back pin. ...