We’ve looked in some detail at the options available to you for the gemstone in your ring. Now it is time to think about the metals it could be made from.
The four precious metals most often used in jewellery are gold, platinum, palladium and silver. All metals used in jewellery are alloys, i.e. combinations of metals added to the precious metal to improve workability and hardness.
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• Which metal you decide to use will depend on your aesthetic and your budget, and the colour which best suits the wearer
• Yellow gold is the simplest and most straightforward metal, the easiest to work and most traditional. An alternative is ‘rose gold’
• Rose gold has a higher percentage of copper. It is as well to have a rose gold wedding ring made at the same time to ensure the same colour
• There are three principal options if you want a white metal. Platinum is the best but also the most expensive
• Hallmarking is your guarantee of quality. It is mandatory in the UK but not in the US, and online purchases may not be hallmarked. Beware of nickel in white metals purchased in the USA
• Fashions in ring metals change constantly. At the time of writing it is moving away from white metals to warm yellow and rose golds.
PRECIOUS METAL ALLOYS AND QUALITIES
For jewellery, each manufacturer and maker has their own closely guarded preferred alloy composition. There is constant development and experimentation to improve the characteristics of these alloys as the different combinations influence colour, durability, hardness, lustre and workability for both casting and forming.
Some alloy metals are more expensive than others. For example, 9ct white gold may be more expensive than 9ct yellow gold if the alloy in the former is palladium and it is plated with rhodium, whereas the alloy of the latter may be copper and other less precious metals.
It is important to note that the wedding band must be the same metal and metal quality as the engagement ring or one will wear the other away owing to the different hardness of different precious metal alloys.
A caution about nickel A further caution about white metal alloys is about nickel. Nickel is a common allergen and causes contact dermatitis in about 10 of the population. Its use in jewellery in the EU is controlled (European Nickel Directive 1994) and most fine jewellery sold in the UK contains no nickel. This is not the case with jewellery from the USA. If you buy a white gold ring in the USA it is likely to contain nickel. When the rhodium plating wears off, as it will, the wearer can become sensitive to the nickel in a fairly short time scale and the ring will become unwearable. I have had to remount a number of rings completely for clients who have bought online and from the USA.
Hallmarking is a safeguard All precious metals sold in the UK must be hallmarked as an independent guarantee of quality and purity. The hallmark will tell the consumer what percentage of alloy is included in the precious metal they are buying and ensure it does not contain any forbidden alloys.
It is the retailer’s responsibility to ensure that the jewellery carries a UK or EU recognised hallmark, and it is illegal to sell precious metals in the UK without such a mark. In the USA and other countries hallmarking is not always required, and rings bought online may not be hallmarked, so it is more difficult for the consumer to be sure of the quality of the metal.
Gold for jewellery comes in different qualities, or carats, and sometimes in a range of colours, depending on the alloys used in making the final article.
In its un-alloyed state, gold is a highly sought-after precious yellow metal which, for thousands of years, has been used as currency, a visible symbol of wealth and self-adornment. Its chemical symbol is Au from the Latin aurum, meaning shining dawn.
Gold is found in igneous rocks and quartz veins, or in the form of nuggets and grains in river beds. The main mining areas are Africa, the USA, the former USSR, Canada,
Australia and South America. ‘Fair trade’ and ‘fair mined’ gold is available in the UK.
Gold is dense, soft, shiny and the most malleable and ductile of the known metals. Pure gold is 24ct. The purity of commercially sold gold jewellery ranges from 9ct at the lower end through 14ct and 18ct to 22ct. Pure gold is too soft to be practical for jewellery.
Rose gold Rose gold gets its characteristic pink hue from a higher percentage of copper in its alloy mix. The depth of colour will depend on the exact proportions of copper and other alloys, so one 9ct rose gold ring will not necessarily be identical in colour to another if they are made in different workshops. If you plan to have a rose gold engagement ring, it will be as well to consider making the wedding band at the same time, or at least by the same workshop, to ensure the colours match.
White gold Gold is yellow. Lots of people assume that there is a special sort of gold which is white. Sadly, this is not the case. White gold is achieved by mixing yellow gold with white alloys, such as cobalt, zinc, palladium and platinum.
Then it is finished by plating with rhodium, which is a shiny white and very expensive metal. The external white colour which you see is therefore rhodium and not gold. This is why there is no visible difference in the appearance of 9ct and
18ct white gold, unlike 9ct and 18ct yellow gold which are clearly different colours owing to the different proportions of yellow gold in the mix. In time, rhodium wears off the shank of a white gold ring, and it will have to be re-plated to keep it white and shiny.
This usually means that every two–three years, or perhaps even more frequently, the plating on both the wedding and engagement rings will need to be replaced. There are three considerations here.
Firstly, re-plating rings with rhodium is not cost-free, and if you are thinking of 18ct white gold instead of platinum in order to keep the costs down, you will spend the difference on re-plating within a short space of time.
Secondly, in order to re-plate a ring, all the old rhodium has to be removed. You do not just re-plate on top of the existing rhodium. This can cause additional wear to the metal in the ring, especially if it is done every couple of years, so if the shank is quite thin it might eventually have to be replaced altogether.
Thirdly, if you simply prefer the shiny white appearance of rhodium over the rather dull surface that platinum and palladium settle into in a short time, you may decide that it is worth the bother. If that is the case, consider 9ct white gold rather than 18ct. It is harder because it contains more alloy than 18ct, and the alloy is often palladium, a hard white platinum-group metal. A further advantage arises because 9ct gold is 37.5 gold and 62.5 white alloy, so it is therefore whiter than 18ct gold and the wear on the plating doesn’t show up as much. This means it may need to be re-plated less often.
A plain white gold wedding band will show up the wear much more than a white gold engagement ring, and more quickly. The engagement ring will typically display wear on the inside of the hand where it is least noticeable, whereas the wedding ring turns constantly on the finger, so wear will be all around the band and be more visible.
In the past, when a white metal was required in jewellery, white gold was the only economical alternative to platinum, and it is much harder and more durable than silver. However, palladium now has its own hallmark and may be chosen as a cost effective and durable white metal alternative to platinum or white gold.
Platinum is a naturally white metal so a platinum ring will never change in appearance (unlike white gold), and it is hard and strong. Because it is white, a platinum setting enhances the brilliance of diamonds and other gemstones so it is the best metal in which to set diamonds, but it is also the most expensive option. Along with palladium, it is generally used for the mount of diamonds in yellow or rose gold rings so that their colour is less influenced by reflected yellow or pinkish tints.
In the UK, platinum jewellery is typically hallmarked at 95 purity, making it purer even than 22ct gold (91.67).
The remaining 5 is made up of alloys which improve its workability.
Platinum is hypoallergenic, so is a good choice for anyone with metal sensitivities or allergies. With wear, it does lose its shine and will dull down very quickly to a light grey metal, which many people do not find attractive. So if you want a shiny white metal ring you may choose white gold instead or have your platinum plated with rhodium.
Palladium has been used in jewellery for many years, most commonly as a mount for diamonds in a yellow gold ring, or as an alloy in platinum and white gold jewellery.
It is now used increasingly in its own right as a jewellery metal since receiving its own hallmark in 2009. It has become particularly popular as an alternative to platinum and white gold for reasons of both cost (similar to the cost of 14ct gold) and colour – it is another naturally white metal, but world supplies of palladium are limited and the cost has increased owing to its use in jewellery.
Platinum and palladium are very close to one another on the chemical periodic table and share many physical characteristics. Palladium jewellery is as pure as platinum, and is nearly as hard, but palladium is half the density of platinum so does feel much lighter on the hand, and may wear less well over the years. Like platinum, it loses its shine quickly, and it is a slightly greyer metal which is why it is more popular for men’s wedding bands where a white metal is required. It is, however, used increasingly in engagement rings for both genders where budget is an issue.
One word of caution: palladium is difficult to work owing to its brittleness in manufacture. This is not a problem in wear, but it does mean that palladium rings can be more difficult to resize, and sometimes the solder line becomes visible, although this can be overcome by rhodium plating.
Silver jewellery is generally Sterling silver, which is 92.5 pure. It is much too soft a metal to use for a ring which is to be worn for a lifetime, and it is not hard enough or strong enough as a medium for setting diamonds, so it is not used for diamond engagement rings or any rings with precious stones. If you are considering silver on its own or set with a semi-precious stone like amethyst, do be aware that this ring will not last forever. It will need to be designed with a much heavier shank and setting, will become misshapen and the surface will look a bit battered within a few years.
Read On – Chapter 12 is all about choosing the right shape for your diamond or gemstone, and avoiding the mistakes which people often make.