Diamond Size Comparison – how to choose the best diamond for your special ring

Planning on buying a diamond for a special ring? Not sure where to start? Well, they say diamonds are a girl’s best friend and this is certainly true! But finding the perfect engagement ring or any other diamond ring can be a mine field, especially when trying to find the perfect diamond. Sourcing the perfect diamond takes time and knowledge and here at Diamond Boutique, we advise all of our clients to do some research before committing to buying a diamond.

There are lots of things to look out for when buying a diamond for that special ring. The 4Cs are a great starting point and then you’ll need to consider which shape you’d prefer and the cut as well as other factors for example the metal used for the ring and the setting for the diamond. Here we’re going to concentrate on ensuring you get the best diamond for your money by doing a diamond carat size comparison. We’ll take you through the different shapes of diamond and also for those of you who fancy being a little different how the various gemstones compare.


Different Diamond Shapes


Diamonds come in lots of different shapes and an endless list of sizes. The most common shapes are round, princess (square with sharp edges), marquise (elongated shape with points at the top and bottom), emerald (rectangular with soft corners), pear, oval and heart shape. Each of these shapes will have different ideal dimensions per carat. This is often overlooked by most people looking to purchase a diamond and is explained further below.


Round diamonds


So, the most obvious starting point for a diamond carat size comparison is a round diamond. These are the most popular shape of diamond for engagement rings. They are classic and traditional and make for show stopping engagement rings. Round brilliant diamonds have 57 or 58 facets creating an amazing sparkle.
Diamonds are measured in two ways; firstly each diamond will have a carat weight. The word carat comes from the Greek word ‘keration’ and refers to a ‘carob seed’ which has been used to measure jewellery throughout history as the seeds are generally viewed as being consistent and uniform in their weight. It is important to realise that the diamond’s carat weight refers only to how heavy the diamond is. This means that the heavier the diamond, the bigger the carat weight will be. One carat is equal to 0.2 grams. Carat weight is an important factor when judging the quality of a diamond. Often the bigger the stone, the more valuable it is. However, the cut, colour and saturation are also important in determining the stone’s value.

Secondly, diamonds will have a measurement in millimetres. For example, a 0.5 carat round diamond should measure 5.2 millimetres, a 1 carat round diamond should measure 6.5 millimetres in diameter and a 2 carat round diamond should measure 8.2 millimetres. For round diamonds, this measurement is their diameter; other shapes may have more than one measurement (height and width).

However, not all diamonds conform to these exacting standards as they are naturally formed precious stones and upon being mined have been cut by human hands. This means that some 1 carat round diamonds may not reach the standard dimensions of 6.5 millimetres. They may weigh the correct 1 carat but their dimensions in millimetres may not be big enough.

So, how can the diamond have the correct 1 carat weight but not be big enough in its dimensions? Well, the answer to this is that the diamond may be holding its weight in the girdle. As you can see below, the diamond is made up of three parts, the crown, the girdle and the pavilion. When you purchase a diamond and put it in a ring, the area that you will see is the crown and the area below the girdle will be hidden in the basket of the ring. So, if you buy a diamond that weighs one carat but doesn’t have the correct dimensions on the crown, you are buying a diamond that is essentially over-priced. If the dimensions are less than 6.5 millimetres, you could purchase a 0.9 carat diamond with the same dimensions on the crown for a much lower price!

Although always measured in carats, the dimensions of the diamond are a really good indication of how well a diamond has been cut for it to reflect the maximum amount of light and thus a great indication as to whether you are getting value for money and not being taken advantage of by your jeweller.

Once you’ve made a great choice on the carat size and dimensions of the diamond, that isn’t the end of the story! Two diamonds weighing the same 1 carat and measuring the same 6.5 millimetre dimensions can still vary dramatically in price. The cut, colour, clarity and certification will have a large impact on this.


Gemstone Dimensions in comparison to Diamonds Dimensions


So, you’ve done a diamond carat comparison but now you’re thinking you’d like to consider the other options. A beautiful gemstone ring can be an amazing alternative to a diamond for people out there who like a splash of colour. A gorgeous gemstone can make a ring even more unique and can compliment someone who is less traditional.

How do gemstones compare to diamonds in a carat size comparison? As each gemstone has a different density, each gemstone will have different size dimensions per carat. So, a diamond, a sapphire and an opal of 1 carat in weight will all have different dimensions in size. Often, coloured gemstones are usually bigger in size for their carat weight, so a 1 carat sapphire will be larger than a 1 carat diamond. To compare a 6.5mm diamond weighing 1 carat with a 6.5mm sapphire will weigh 1.14 carats and an opal of the same dimensions and cut will only weigh 0.61 carats.

However, with gemstones, carat to value is more difficult to determine. Qualities such as the gemstone’s cut, clarity and colour can have a dramatic impact on the price of the stone. For example, a high quality rare sapphire of one carat can be worth much more than a larger stone of 5 carats.

So, the advice that we would offer here is to buy a gemstone based on the size of the stone not the carat weight. Diamonds are more standard in their dimensions (although you still need to be aware of the differences outlined above). Gemstones are not cut to as strict standard dimensions as diamonds so decide on the size dimensions that you are looking for and search for a gemstone that meets these demands. The reason that gemstones don’t fit these strict standards as easily is because they are cut to maximise their best asset: their colour! Gemstones will often have more weight in their pavilion than most diamonds will. Having a heavier pavilion can benefit the colour of the gemstone, making the colour deeper.


Tricks in the trade to make the diamonds seem larger


Everyone has a budget and after carrying out a diamond size comparison you realise that the wearer of the ring loves a large stone, but your budget doesn’t quite stretch to the preferred size of diamond. There are lots of tricks in the trade that can help to keep your betrothed happy and your pocket equally happy! Below are some ideas for making the centre stone look bigger!


Shapes can make them look bigger!


So how big will the diamond or gemstone look? Some people prefer a more subtle look with a smaller diamond and others prefer their engagement ring to look as sizable as possible without breaking the bank!

Certain shapes make the diamond look bigger than others. The best shapes with this quality are emerald, oval, pear and marquise diamonds. These diamonds most certainly look the biggest per carat weight in comparison to all other shapes. The reason for this is that the cut ensures that the majority of its weight is on the crown and not below the girdle. Marquise, oval and pear shaped diamonds are elongated shapes and that also contributes to them looking larger. Oval is a popular alternative to the classic round diamond. An oval engagement ring is still traditional and classic but looks larger than the ultimate classic design including a round brilliant diamond. Marquise shaped diamonds are rather contemporary and make equally unique designs for engagement rings.

A fine example of an oval diamond taking centre stage is our Arya Diamond Engagement Ring. This includes an oval diamond at its centre and here at Diamond Boutique you can customise your ring by choosing the size of the diamond at its centre. You can choose from a dainty 0.5 all the way to a 2 carat stone at the centre. As we offer a bespoke service, if you wish to choose a stone that is bigger or somewhere in between you can do this with us too!


The cut of the stone is important too!


How can the cut make the stone look bigger? Put simply, when a stone has lots of brilliance (which means sparkle to you and I) it looks larger to the eye. For a diamond to have great brilliance, it needs to have a great cut. Diamond cuts are graded from ‘poor’, to ‘fair’, to ‘good’, to ‘very good’ to ‘excellent’. A poor cut can make a large diamond look dramatically smaller. And, you could find yourself paying over the odds for a diamond that has the carat weight you’re looking for but doesn’t sparkle as you’d expect it to and as a consequence it wouldn’t look as big as it should.

A beautiful example of using shape and the cut of the stone to maximise how big the stone looks is our Ivy Diamond Engagement Ring which features an emerald shaped diamond. At Diamond Boutique, we offer lots of choice to ensure that you get the perfect ring for your proposal. You can customise this ring to suit your needs and your budget. You can choose the carat weight, the diamond quality, the metal and obviously choose this in the desired ring size. The diamond quality offered on our website varies from ‘very slightly included’ to’ very very slightly included’ to ‘internally flawless’. And the colour is from G to E. But if you have other prerequisites or wish to discuss this further don’t hesitate to get in touch with us here.


Choose a stone with a lower grade in clarity and colour


Another way to maximise the size of your diamond is to choose a larger stone but compromise on the clarity and/or colour. How large a diamond looks is not greatly affected by its clarity, so if size is your main priority, then choose a larger diamond with less clarity. Diamonds also come in lots of different colours and if you are happy to compromise on the colour of your diamond for a larger diamond, then that’s another great choice for you.


Accent stones can help!


Opting for a halo around your centrepiece is another way to give the illusion of a larger central diamond. Halo engagement rings are a popular choice and really do make those centre stones look dramatically bigger. Using a ring of small brilliant round diamonds around your centre stone creates a glamorous effect and adds lots of extra sparkle further tricking the eye into thinking that the centre stone is even larger.

Our Vintage Diamond Engagement Ring offers an oval centre stone surrounded by a halo of round brilliant diamonds and the sparkle is further accented by the small round brilliant diamonds that decorate the band. Again, there are lots of options for this ring with regards the size of the centre stone and the colour and clarity. You can also choose to have the band fully set with diamonds or two thirds or half set.


Cluster rings can make the centre stone look huge!


Cluster rings are defined as rings that hold a central diamond and are surrounded by other diamonds that could be the same size or smaller. A cluster ring can also be a ring that has a halo or even a double halo. It can be a ring that has lots of smaller diamonds clustered together to resemble a larger diamond and that is certainly the effect that you’ll create in configuring diamonds in this way. These smaller diamonds are often made from off-cuts from larger diamonds and are thus usually much cheaper than larger stones.

When doing a diamond carat size comparison, the carat weight for a cluster ring is the total sum of all the diamonds put together, whereas with a solitaire ring, the carat weight is in the single diamond. Knowing the carat weight for a cluster ring is important for comparing it to other cluster rings, but is not recommended for comparing a cluster ring to a solitaire ring for example as they’re simply too different to compare. Our Akira Designer Engagement Ring is a perfect example of a cluster ring. It holds in total 73 round brilliant diamonds and has a combined carat weigh of 0.5. It’s a great choice for someone who likes a show stopping ring for a smaller price tag than a solitaire of the same size, colour, cut and clarity.


Choose a slim band and setting


The style of ring will also help to make the stone look bigger. A 6.5mm diamond will look large on a dainty design and even more so on a small hand. But a chunkier design will make the same 6.5mm diamond look smaller. Choosing a slim band with slim prongs with help to make the diamond look larger in comparison.
Our Esha Knife Edge Engagement Ring is a beautiful example of this. This ring also offers a ‘knife edge’ band which gives it a ‘v’ shape and points outward from the finger. This type of band is very popular with solitaire engagement rings and is conversely very comfortable to wear. This ring is also available in a classic 4 prong design and a comfort fit design.


To conclude ...


We’ve considered how to carry out a diamond carat comparison. We’ve considered what a ‘carat’ is and what other measurements we should take into account when buying a diamond. We’ve considered the other factors to take into account when buying a diamond and how to maximise size over the other factors. We’ve also considered how the shape of the diamond can make it look bigger and how important the cut is at tricking the eye with sheer sparkle! We’ve looked at other tricks of the trade to make the diamond look bigger but keep the cost down. And we’ve even considered swapping the diamond for a coloured gemstone and the factors that we would need to consider to get the best stone for your money. If you need further information on the 4Cs of diamonds and ‘How to tell your diamonds apart’ visit our blog and for information on how to keep your diamond looking at its best see our blog on ‘How to Clean Your Diamond Ring’.