Platinum or white gold: which is better for an engagement ring?

Gold is yellow. To make white gold, it is alloyed with white metals such as palladium or nickel, and most white gold rings are then plated with rhodium for a bright, cool white. GIA notes that the plating wears and the ring has to be re-plated occasionally. Brilliant Earth puts it at about six months to a year for a ring worn every day, longer if it is worn carefully.

Platinum is white by nature. There is no plating to wear through, so the colour you see on the first day is the colour of the metal itself, inside and out; it is a slightly softer, greyer white than fresh rhodium. Brilliant Earth also notes that platinum generally needs no rhodium plating.

Next to a colourless diamond both look icy and clean. The difference shows in year two, when a white gold ring may want its first re-plating and a platinum one does not.

This is the part most guides get wrong. Common cast platinum 950 is not harder than 18K white gold. In the 2021 study in Johnson Matthey Technology Review, two cast platinum 950 alloys measured about 134 and 149 on the Vickers scale; the 18K white golds measured 213 and 287.

And yet, in the same study, the platinum alloys wore away about three times less by volume than 18K palladium white gold, and about half as much as 18K nickel white gold and 14K palladium white gold. By weight the losses were closer, because platinum is denser; in plain terms, a platinum ring keeps its thickness and shape longer. When platinum was scratched, much of the metal was pushed to the sides of the scratch rather than shed, and the researchers think this ductility is why it wears more slowly. That is the soft, satin patina platinum owners talk about, and a polish brings the shine back.

Fair caveats: platinum does lose some metal; the study was paid for by the platinum industry association and is one of very few direct comparisons; and a softer metal can bend or dent where a harder one would chip. For prongs that is usually the lesser evil: a bent prong can be pushed back, a broken one has to be replaced. GIA also notes that platinum prongs are less likely to break. Whichever metal you choose, have the prongs checked once a year.

• Choose platinum if low maintenance matters most: she wears the ring every day and you want it to stay white without re-plating; she has sensitive skin or a known nickel allergy; you like a heavier ring that feels solid on the hand.
• Choose 18K white gold if the budget matters more; she prefers a lighter ring; an occasional jeweller visit for re-plating does not bother you.
• Not sure what she wears? Look at her hands for a week. If she wears silver-tone jewellery, both are right. Our guide Yellow, white or rose gold? shows how to read it.

• Metal: Platinum 950, offered on our rings, earrings and pendants next to 14K and 18K gold.
• Lead time: made to order in up to 21 business days, the same as gold, often sooner.
• Price: at Kove the ring without its centre stone costs more in platinum than in 18K gold; the centre diamond costs the same. The product page shows the exact price as soon as you choose platinum.
• How to order: open the ring you like, choose Platinum 950 and order as usual. Questions about the alloy or the size? Write to us.