An expert's guide to buying diamond rings

Whether you are looking for a ring for yourself, an engagement ring for your partner or a Valentine’s Day present for the special person in your life, auctions are a great way find to the perfect item.

In the auction room prices are typically lower than retail and the choice available can be far greater. Here we explain what to look for when you’re deciding what to buy.

A typical specialist jewellery sale will offer plenty of different styles and sizes of diamond rings dating across a range of periods, while many general sales have a good number of examples too.

Popular types available include classic solitaire rings or diamond eternity bands.

An 18ct gold and platinum solitaire ring set with a brilliant cut diamond (approximately 0.50ct) – £460 at Chalkwell Auctions in June 2022.

If you’re after a ring with multiple stones, you’ll find those on offer as well.

Make sure you know what finger size you need before you start searching – you’ll find the size noted in the catalogue entry (it’ll normally be a letter between F and T). However, it’s not difficult to get a ring resized if necessary and many jewellers across the country can arrange this for you.

The Four Cs

All gemstones are classified according the four ‘Cs’ – carat (weight), colour, clarity and cut.

Cut: This refers to the way the diamond has been shaped with the symmetry and proportions affecting the sparkle.

Carat: This is a measure of a diamond’s weight. Crucially, this is not a measurement of the size of the diamond although larger diamonds will often be heavier.

Colour: This is a measure of a diamond’s purity. The purer the stones, the less inherent colour they contain and therefore they will reflect more natural light, meaning the brighter its appearance. Hints of yellow or brown will typically devalue the stone.

Clarity: Most diamonds have small marks, fractures or imperfections called ‘inclusions’. While some are not visible to the naked eye, most can be seen under magnification and will typically be mentioned in an auctioneer’s condition report.

The four Cs are key factors that will affect the value of the diamond ring.

In general terms, the more carats, the higher the price; the purer the colour, the rarer it will be; the clearer a diamond, the more sought after it becomes; and the more beautifully cut the diamond, the more desirable it is.

In terms of ranking the importance of these factors, it is basically a matter of personal preference and managing your budget.

A diamond ring by Tiffany & Co with a square-cut diamond (weighing 0.54 carat) and set with brilliant-cut diamonds, mounted in platinum. Offered along with a case and box it sold for £1000 at Noonans.

For some people, the size of diamond is the most important criterion, in which case they may accept some ‘inclusions’ in order to obtain the larger stone within their given budget.

Others may prefer a higher-grade stone and accordingly settle for a smaller size.

Many lots offered at auction may have an indication of these inherent qualities noted in their catalogue entries. Often the best quality gemstones offered at auction have been submitted, prior to sale, to a professional independent laboratory testing (a service provided by a number of different grading bodies).

Always read the lot description carefully before bidding and feel free to contact the auction house to request a condition report or more photographs. If the auction house selling the item you are interested in is nearby, you can also attend a viewing day to inspect the lot in person.

A platinum full eternity ring with a row of brilliant cut diamonds – £600 at Sworders in June 2022.

Further factors

Other things to consider when buying a diamond ring at auction include:

Shape: People have different preferences as to the shape of the diamond. Popular shapes include round, brilliant, pear, princess, oval, cushion, emerald and radiant diamonds.

Band: the material used for the band (the part of the ring that goes round your finger) is also an important choice. Traditionally, yellow gold was widely used but plenty of rings nowadays have white gold, rose gold or platinum for the band.

Setting: This refers to how the diamonds are placed on the ring. Sometimes settings are simply categorised as ‘high’ or ‘low’, but settings are often fashioned into a key part of the ring’s design, for instance prong-set rings, bezel-set rings, halo-set rings and cluster-set rings.

Age: The date a ring was made can also be a factor for some buyers. Some people are drawn to antique and vintage pieces which offer a sense of history, quality and the individuality that allow the wearer to stand out from the crowd. Others may be seeking a more contemporary look.

For more information on buying rings at auction, you can also read our guide to engagement rings.

What to do next

Decide how much you’d like to spend and use the search facility on thesaleroom.com to find diamond rings coming up for sale.

You can filter your search by, among other things, price and by location of the auction house to narrow down your selection.

To research recent prices at auction to see how much different diamond rings items sold for you can also try out the Price Guide.

If you are new to bidding check out our guides to buying at auction – it’s easy once you know how.