Our guide to help you understand jewellery metals reviews those most commonly used today. We know that choosing the right metal for your jewellery can be overwhelming if you don’t know a few basics about jewellery materials. You know the kind of stone your engagement ring (or another type of ring) will be, but you aren’t as certain when it comes to the metal type. Here is a short summary of those metals commonly used for jewellery.
Gold, when found in nature, has a natural deep yellow colour in appearance and when refined, its purity comes to 99.999% pure gold. In jewellery related terms, gold’s purity is measured in carats and 99.999% pure gold is 24 carat(K).
To create gold in a form in which it can be used for jewellery purposes, it has to be melted down, in other words, alloyed with other metals like palladium, silver, copper etc. This alloying process gives the gold different properties and characteristics to what it would naturally have like hardness, lower density, different variations of colour etc.
Gold colours and their alloys
Yellow gold – pure gold, silver, copper, zinc.
Red gold – pure gold, copper.
White gold – pure gold, palladium, platinum, nickel, zinc.
White gold usually has to be rhodium plated (an electroplating process whereby a layer of rhodium is added to the surface of the jewellery piece).
Pure gold can also be alloyed with metals such as iron, aluminium and cadmium to achieve exotic colours like green, blue and even purple. These mixtures, however, are very brittle and therefore their use for jewellery is considerably limited.
- 22K- 91.6% pure gold
- 18K-75% pure gold
- 14K-58.3% pure gold
- 9K- 37.5% pure gold
Platinum which is part of the six PGMs (platinum group metals) is extremely resistant to tarnishing and corrosion. That, combined with its rarity, makes it a perfect metal for jewellery. Platinum, like gold, is also very soft and also needs to be alloyed with other metals to make it usable for jewellery. Metals used for platinum alloying include, palladium, cobalt, copper and ruthenium. Unlike gold which is hallmarked as 22K, 18K, 14K and 9K, platinum is usually hallmarked as Pt or 950. This implies the total mixture is 95% platinum and 5% other metals.
Platinum is one of the densest elements in nature and as a piece of jewellery, its weight will seem very heavy for its size. It’s a beautiful metal and some argue that no other metal’s polish compares to that of platinum, which of course is what you are looking for when purchasing a piece of jewellery.
Another member in the platinum group metals is palladium. Its colour is similar to that of platinum but its density is much less, about the same as 14K gold. While still very rare, palladium is not as rare as platinum. That, combined with its lower density (a palladium band exactly the same size as a platinum band will weigh much less) makes palladium more affordable and a great option for men’s rings which tend to be bigger. Palladium is also usually hallmarked 950 or Pd.