What does ‘white metal’ mean?
We refer to any metal with a silvery white appearance as a “white metal”. Legally, if an item does not bear a hallmark, and therefore has not been assayed (tested) for its metal content, we must refer to it only by its colour: white, yellow, red, etc.
A white-metal jewel will generally be predominantly made of one of a group of metals: platinum, palladium, gold and silver. Contemporary jewellers may also use aluminium, titanium and steel. Most white metals used in jewellery are alloys as they are a mixture of different metals, each chosen for the properties they bring to the alloy. We assess alloys of metals in terms of their fineness, which is recorded in parts per thousand.
Platinum is one of the precious white metals most used in jewellery manufacture. Chemically, it is part of the platinum metals group with the other white jewellery metals palladium and rhodium. These metals are very strong and unreactive, making them excellent materials for use in jewellery designed to withstand daily life.
Platinum is considered precious because of its metallic white colour, its resistance to corrosion and its rarity. Though malleable, it is a very dense material – a platinum ring will feel noticeably heavier than a palladium ring of the same dimensions – and many people appreciate the weight of platinum jewellery. Platinum’s many desirable properties means that jewellers use an alloy of platinum with a much higher fineness than their alloys of gold. Most platinum jewellery is 950 parts pure platinum out of 1,000 (95 per cent); hallmarked platinum will bear a mark reading “Pt 950”.
Platinum may be a strong metal, but platinum jewellery will still get scratched or dented through daily wear. Over time, like all jewellery, the surface of platinum jewels will become matte with fine scratches – a sign of the jewellery’s life. These scratches can be polished or buffed out by trained polishers – get in touch with our Concierge for more information on polishing services – but many people enjoy the patina that platinum develops, as it brings the adamantine lustre of diamonds into sharper contrast.
You can clean platinum jewellery at home by brushing it with a small amount of washing-up liquid on a soft or old toothbrush and soaking in hot water. Rinse the jewel afterwards to remove any residue left by the washing-up liquid. Do not wash jewellery with gemstones in closed-back settings (that have metal wrapped around the back and sides of the stone) as water may reach, and get trapped, behind the stones, potentially leaving a build-up of residue in the setting that may make the stone look less lively.
Platinum does not tarnish in the same way as silver, and platinum’s surface layer only oxidises at 500˚C, so platinum jewels require much less cleaning.
A silvery-white metal of the platinum metals group, palladium looks very much like platinum, but it is the least dense of the group and so platinum and palladium jewels feel very different. The two metals share many characteristics and so their care requirements are largely similar.
Palladium can be beaten to form a very thin – but strong – sheet, a property that makes it useful as a jewellery metal. However, palladium jewels are not as common as platinum because palladium reacts more to heat – it has the lowest melting point of the platinum metals group – and can therefore present more challenges in jewellery designs that require soldering (joining) and annealing (softening) processes that use heat.
Palladium jewels are marked “Pd” and are generally of a fineness of 950 or 999 parts per thousand.
Palladium jewels wear in a similar way to platinum jewels and should be cared for in the same way.
Rhodium and White Gold
Rhodium is another member of the platinum metals group, but it is very rare. It is a bright white, chemically inert, corrosion-resistant metal that shares the strength of platinum and palladium. However, rhodium is less malleable than other precious metals and has a very high melting point, which makes the heating processes of soldering and casting difficult. These properties, coupled with its rarity, make rhodium a useful plating metal, rather than a body metal, for jewellery.
Rhodium is commonly used to plate white gold jewellery. Non-plated white gold typically has a yellowish tinge because pure gold is yellow; gold is therefore alloyed with white metals to change its colour and slightly alter its properties. Though white gold is whiter than its equivalent gold alloys, many jewellers consider it to be too yellow for their designs. White-gold jewellery is thus commonly plated with a thin layer of rhodium, which gives the items a bright, white colour and shiny finish.
Rhodium plating begins to wear from jewellery, particularly from rings and the back of necklaces as they move against the skin, and you may see a yellowish tinge to your white-gold jewels. Jewellery can be re-plated, though some people prefer the softer tones of slightly worn plate. If you send your rhodium-plated jewellery for repair, the work will be finished with an application of a new layer of rhodium instead of the polishing that platinum and palladium receive. Speak to our Concierge for plating services.
As one of the platinum group, rhodium can be cleaned at home in much the same way as platinum and palladium. A soft cloth should remove built-up grease, and diamond-set white-gold jewellery can be cleaned more thoroughly with a soft toothbrush and warm water. Leave the item to soak in the water if the dirt seems stubborn.
A white and lustrous material, silver has been treasured as a precious metal for millennia. Its antibacterial property has made it a useful and popular metal for fashioning cutlery, tableware and jewellery. Before technological developments enabled the widespread use of platinum and white gold, silver was the go-to white metal for jewellery. Much antique jewellery will feature silver settings for white stones, like diamonds.
Pure silver is very soft and is therefore not used in jewellery manufacture as designs require some level of structural support and strength and our jewellery needs to withstand wear and tear. Silver is therefore alloyed with other metals to introduce desirable properties. “Fine silver” is 999 parts silver out of 1,000 parts, while most jewellery is made of “sterling silver”, which is 925 parts silver per thousand. You may also find jewels hallmarked as “Britannia silver” at 958 parts silver per thousand.
Though we often think of silver tarnish that requires cleaning, silver is not very reactive. The characteristic darkened surface we associate with tarnished silver is derived from the interaction of sulphur and oxygen with silver surfaces that are exposed to the air. The sulphur and oxygen bond with the silver, and sometimes also with the metal it is alloyed with (particularly copper), to leave a thin layer of silver sulphide and silver oxide that appears as dark tarnish. Tarnish can be rubbed off using a soft, dry cloth or a silver cloth that is specially impregnated with chemicals. Chemical cleaning, including submerging jewels in silver dip, should generally be avoided for jewellery as jewels often have constituent parts made of other metals and gemstones that can easily be damaged by cleaning chemicals. Use a plain cloth to clean silver jewellery if you are unsure.
Wear your silver jewellery! Interaction with skin keeps tarnish at bay.
Simple rules to keep all your metal jewellery in tip-top condition:
Store all jewellery separately to prevent scratches. Even metals known for being particularly hard, like platinum and rhodium, will scratch, especially when in contact with hard gemstones like diamonds.
Remove jewellery when cleaning and when completing daily beauty regimes. Cleaning products, make-up, hairspray and perfume all contain chemicals that can interact with the surface of your jewellery. Some chemicals will attack the metal, stones and enamel of your jewellery, others may leave a build-up of residue.
Remove jewellery for sports and exercise. Swimming in chlorinated, fresh and salt water can leave chemicals on metals and stuck behind stone settings. Lifting weights or using gym equipment can scratch and dent rings.
Wearing our jewels gives a softness to their appearance, so enjoy your jewellery.