The Definitive Guide to Buying a Diamond Engagement Ring

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What to look for in a diamond engagement ring

Next to buying a home or a car, buying a diamond engagement ring is one of the biggest purchases you will ever make. As well as being an investment, the ring you select is the symbolic beginning of married life. It’s a decision that you want to get right- but with questions about carat weight, diamond shape, band metal, ring setting and diamond cut floating around your mind, it can be tricky to know where to start. Our definitive guide to buying a diamond engagement ring will lead you through the process, so you know exactly what to look for when selecting the ring.

The four Cs: Carat, Cut, Clarity and Colour

The first thing to get your head around is the idea of the 4Cs; carat, cut, colour and clarity. Developed by GIA, the Gemmological Institute of America, the blend of the 4Cs determines what your diamond engagement ring will look like, how it will appear to the naked eye, any blemishes or inclusions and its brilliance. This might sound daunting, but as when purchasing anything else of value, buying an engagement ring means determining your priorities and finding the right balance for you.


Perhaps the one aspect of the 4Cs that you might have an opinion on is that of carat. You’ll often hear people talking about 1 carat, 2 carats or more and what carat means is diamond weight. How large the engagement ring looks on the finger is largely determined by its carat. Generally speaking, the higher the carat, the higher the price. Bear in mind though that diamond prices do not increase smoothly, there is a jump upwards in each weight category, so for example a 1.01 carat diamond can be 20% more expensive than a 0.95 carat diamond, with no visible difference. To make things even more confusing, different shapes of diamond can have a different price per carat, so there is much to be guided on. But carat weight is not the only thing to consider.


In this sense, the cut of a diamond refers not to its shape, but to the polished facets of the stone. It is the cut of any diamond that gives it life and sparkle. Angles precisely calculated and interconnected, ensuring that light reflects perfectly in and around the diamond and through the top. When someone shows off their new engagement ring, you’ll often see them moving their ring finger to allow the diamond to capture the light. The cut of the diamond you purchase is vital to how it sparkles and unleashes that light.


Diamonds were formed billions of years ago beneath the earth’s crust under intense pressure and heat, and during this process, slight blemishes or inclusions were created too. A flawless diamond is extremely rare. The GIA grades diamonds from FL (flawless) to I3 (inclusions 3). As with everything else in the buying of a diamond engagement ring, it’s about balancing your wants and needs with the other aspects of the 4Cs. From a practical perspective though, you should be looking for a diamond that looks ‘eye clean’, without any visible inclusions to the naked eye, which should be possible in the clarity grade VS1- SI1 range. You can ask your bespoke diamond specialist to view the diamond under the 10x magnification of their jeweller’s loupe. As an example, inclusions on a VS2 clarity graded diamond may not be visible to the naked eye but will show up under the loupe.


It may be difficult to imagine but there is a whole rainbow of diamond colours to consider, a sliding scale from D right through to Z. As a general rule, the less colour, the rarer the diamond. The D end of the scale is where you will find the best quality diamonds, colourless to appear almost white. But as we’ve said before, choosing your diamond engagement ring is a delicate balancing act. Colour has to be weighed against the other 4Cs, as the shape you pick will impact how much colour it reflects. It is not always necessary to purchase a D coloured diamond to achieve the desirable white diamond colour. Fancy colour diamonds form a separate and different category in themselves, with yellow being the most common fancy colour for a bespoke engagement ring.

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If you are looking to create a bespoke diamond engagement ring, look for inspiration in magazines, or on the internet, and start to get an idea of what you like, or don’t like. Clients will often show me an Instagram post, or similar, as a starting point for discussions.

Henry Pruwer

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Diamond Shape

Another big decision is the shape of the diamond. A round diamond is the most popular choice for a diamond engagement ring but you could also opt for what is known as a ‘fancy shape’ with an oval, rectangle (emerald-cut), heart or pear shape stone. You may also hear of the princess cut diamond, an inverted pyramid of a diamond that appears square in shape from above; 0r the octagonal Asscher shape.

As the name suggests, the brilliant-cut diamond has multiple facets, totalling 58. Most round diamond engagement rings have this brilliant cut. Look very closely at the round brilliant diamond, and you will see the many facets of the diamond reflecting out the light.

Close to the round brilliant diamond in sparkle and desirability, the princess cut diamond is essentially one half of a rough diamond. Cut and inverted into its setting, the princess cut diamond gives the appearance of a square diamond.

An increasingly popular diamond shape, the emerald cut features four longer facets within a square or rectangular shape, encased by bevelled corners. This cut symbolises understated elegance, with less fire but more depth.

The pear shape or teardrop cut is distinctive with its round top and tapering point. Careful choice of stone is important, as poorly cut stones can have dark corners and black reflections. A well-cut pear shape diamond in a bespoke setting can look stunning.

Allowing you to blend both the brilliant cut and the emerald cut, the radiant cutting style brings the many facets of the brilliant cut to a square or rectangular style of diamond.

The original Asscher Cut features layered facets within a square diamond shape. The perfect geometry of this cut makes it unique. An Asscher cut solitaire is often combined with trapeze shaped side stones, to create a very individual ring.

The cushion cut diamond is either square or rectangular with rounded corners which makes it both durable and modern in appearance. The curved edges on the typically square stone give the diamond a pillow like look, hence the cushion cut moniker.

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When a client comes to me to create an engagement ring as part of a surprise proposal, I advise them to listen very carefully to hints from their partner. Usually, if you listen, you can pick up ideas of the type of setting, or band colour that they like.

Henry Pruwer

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Choosing the right metal for your diamond engagement ring

Hopefully, you will now have a greater understanding of diamond shape and the 4Cs. The next question to ponder is that of metal for your engagement ring band. Things to consider here are the type of metal you and your partner like and how the metal might look set against the diamond’s colour. And of course, what metal you would like for your weddings rings. There are many metals to consider for your engagement ring band, but here are the most popular:


Both stronger and rarer than gold, platinum is perhaps one of the most sought after metals for engagement ring bands. As platinum is a grey-white metal, it can show off your diamond to its best advantage, emphasising the colourlessness of the diamond. Due to its durability, platinum is extremely popular for wedding bands. Platinum claws or prongs will also securely hold your precious diamond in place on your engagement ring.

White gold

White gold is made by mixing gold with nickel or palladium alongside copper and zinc. Look for at least 14K white gold to achieve the necessary durability for your engagement ring band. At Henry Pruwer we only use 18-carat gold, which contains 75% pure gold. White gold is usually plated with rhodium to give it extra whiteness and brilliance. Over time, the rhodium can wear off, but your jeweller can easily repolish and rhodium plate your ring. White gold bands may not be advisable for those who are prone to metal allergies, due to it often being alloyed with nickel.

Yellow gold

Yellow gold is the traditional choice for both engagement ring bands and gold wedding bands, with a distinctive yellow-gold colour which comes from the yellow gold mixed with metals such as copper. Extremely hypoallergenic, yellow gold works particularly well with diamonds of a lower colour scale because any yellow tones to the diamond will blend with the ring metal. Yellow gold is also popular for vintage style and art deco engagement rings, as well as a setting for fancy yellow diamonds.

Rose gold

Contemporary and distinctive, rose gold is a blend of copper and silver, working together to create a strong material for your engagement ring band or wedding bands. Increasingly popular, rose gold comes in all manner of hues and is often an affordable option. Similar to white gold, rose gold may not be suitable for those with metal allergies due to the copper.

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Apart from the GIA there are many other organisations offering diamond certificates, many of these should be treated with great caution. A certificate can add a level of confidence to your purchase, but it is fundamentally all about the diamond itself; the certificate will stay in a drawer.

Henry Pruwer

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Choosing the right setting for your diamond engagement ring

With so much care and attention lavished on finding just the right diamond, the next step is finding just the right setting to hold it perfectly in place. But as well as keeping your diamond secure, the setting impacts greatly on the look of your dream ring, showing every facet of its beauty.

The claw/prong setting

A classic for your diamond ring is the prong setting. Delicately supporting and uplifting the diamond, the prong setting works to showcase a single diamond- which is often known as a solitaire. Encased in its prongs, the diamond can be seen to its best advantage. The number of prongs can vary from 4 up to 6. So too, the prongs may be rounded or in a cathedral setting emerging from the band itself. At Henry Pruwer, we use the finest diamond setters, creating a ‘talon’ finish on each prong. This keeps the diamond secure, whilst tapering to allow the maximum light through with elegance.

The bezel setting

Instead of prongs, the bezel setting uses metal to encase the outline of your diamond and protect this precious centre stone. Extremely secure, neat and with a more streamlined plane, the bezel setting is ideal for those with active lifestyles or occupations. The bezel setting is also revered for its contemporary style, and both a full and partial bezel is possible.

The halo setting

When you take a centre stone and encircle it with yet more diamonds, this is known as a halo setting. Halo diamond engagement rings enhance the beauty of the centre diamond with the addition of smaller diamonds. This makes the central diamond appear larger, and the ring more impressive as a whole. The halo setting can be used to create a bespoke piece that is particularly distinctive with the addition of a pavé wedding band.

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It can be a very anxious time for the person who is undertaking the proposal and they feel a lot of pressure to ensure everything is right. However, it’s not always possible to discreetly find out your partner’s ring size before the proposal. I will always adjust the fit of the engagement ring at a later date, to ensure the ring fits perfectly. This gives the necessary peace of mind.

Henry Pruwer

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Choosing side stones to complement your diamond engagement ring

As well as the prize that is the centre diamond in your engagement ring, you may also want to introduce additional gemstones known as side stones. We’ve talked about diamond colour already, but you can also use side stones to introduce a new colour or a new shape to your diamond engagement ring.

Baguette side stones

From rectangular to square in shape and with either straight or tapered edges, baguette diamonds tend to sit either side of the central stone. Unless a brilliant-cut, each baguette side stone diamond will have 14 glittering facets, helping to elevate and enhance the central diamond.

Pavé diamonds

A charming way to add new stones to your engagement ring is with Pavé or channel set diamonds in the band. Pavé comes from the French for ‘to pave’, in other words, that the band is paved with diamonds.

Other gemstones

Whilst a diamond is the traditional choice for an engagement ring stemming from the famous De Beers ‘a diamond is forever’ campaign of 1947, gemstones such as sapphires or emeralds used as side stones can greatly add to the beauty of a diamond engagement ring.

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Everyone has a budget, whether that figure is £3000 or £3 million. My job is to source the very best diamond for that particular budget from the diamonds that are available around the world, presenting the best options to my client to choose from.

Henry Pruwer

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Diamond certificates

Most diamonds offered online and in stores will come with a certificate. Within the diamond industry, the most widely accepted certificate is from the GIA, the Gemmological Institute of America. A GIA certificate will confirm whether a stone is natural or not, together with other characteristics. When buying a diamond engagement ring you should be aware that a certificate alone does not guarantee any sparkle! All diamonds can be certified, whatever their quality. A diamond specialist can guide you to understand the certification and help choose the right stone for your needs.


As we have seen in our ultimate guide to buying a diamond engagement ring, buying an engagement ring isn’t necessarily a quick process, and nor should it be. The diamond engagement ring you buy is a symbol of your love, your commitment and your intention to build a life together forever. It’s not a time for cutting corners but equally, buying an engagement ring should be exciting, fun and filled with promise. With Henry Pruwer as your diamond specialist, Henry will lead you on the journey to creating a bespoke diamond engagement ring, making an intensely complicated process easier, guiding you through the myriad options and distilling your ideas and hopes into a piece to be treasured always.


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I usually advise a 6-week timeframe to create a bespoke piece. This is, of course, in an ideal world and sometimes we don’t have the luxury of several weeks or months to create an engagement ring. We can source a fine diamond ring within days, or even hours, if extremely urgent. But for the best choice of diamonds, try and leave as much time as possible.

Henry Pruwer

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