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DIAMOND BUYING GUIDE

If you're shopping for diamonds, you've probably already done some research into the 4Cs: colour, clarity, cut and carat weight. If not, don't worry! You'll find illustrated explanations of the 4Cs further down this guide, along with Frequently Asked Questions about buying a diamond. 
 
The 4Cs diamond grading system was developed by GIA, the leading source of knowledge, standards and education for gemstones and jewellery worldwide. If you'd like to learn more about the 4Cs and the history of diamond grading, we recommend downloading the GIA 4Cs brochure and reading this article about Diamond Quality Factors. The GIA app also contains a wealth of information about the 4Cs including interactive tools, expert articles and videos. It's available to download on Android and iOS
 
While it's important to educate yourself about the 4Cs, it takes years to learn everything there is to know about diamonds. This is why we offer a free, no-obligation consultation to discuss your requirements in person and help you choose the best diamond for your budget.
 
In addition to the 4Cs, it's important to consider the shape of your diamond. This will have the biggest impact on the look of your jewellery. When you visit us for a consultation, we'll show you our sample sets of the most popular diamond shapes and carat weights so you can compare them side-by-side. Scroll down to learn more about the different options with our illustrated guide.
 
When buying a diamond, the most important thing to remember is that nobody can see the paperwork! If you like a diamond, it doesn't matter whether it's 0.90ct instead of the full carat, VS2 instead of VS1, certified or uncertified, natural or lab-grown, or what you paid for it. A beautiful diamond is a beautiful diamond - as long as you love it, that's all that matters! 

Diamond Buying Guide
Frequently Asked Questions 

Which of the 4Cs is most important?
 
We consider cut to be the most important. While the term 'cut' is also used to describe the overall shape of the diamond (for example Emerald Cut or Princess Cut), in grading terms it refers to the quality of the stone cutting itself. Therefore when we talk about the 4Cs, we are referring to the assessment of the cut rather than the stone shape. A poorly-cut stone will lack sparkle and fire, so it will be disappointing to look at no matter how good the colour or clarity is. After cut, we consider colour to be more important than clarity. This is because a yellow diamond is obvious to a casual observer, but nobody is likely to examine your diamond with a magnifying glass! Even fairly large inclusions can be disguised by the sparkle of a well-cut stone with brilliant facets and a nice white colour.
 
The fourth C stands for carat weight, so this relates to the weight of the stone rather than any specific quality standard. Unless you have an unlimited budget, the weight of diamond you choose will be limited by the amount you have to spend. There will often be a trade-off between carat weight and clarity. For example, do you choose a larger stone at VS2 clarity or a smaller stone at VVS1? Often it's a case of viewing a few stones in person and seeing which you prefer.
 
What is a certified diamond?
 
A certified diamond has been submitted to a laboratory for independent testing to determine its colour, clarity and cut. The grading report will document the carat weight and measurements of the stone, and some will also include a map of any inclusions. The leading certifiers are GIA (who invented the 4Cs grading system) and IGI, but there are several testing laboratories worldwide offering their own grading reports based on GIA's 4Cs grading system. You will pay more for a certified stone than an uncertified one. GIA is considered to offer the best standard of grading and therefore GIA-certified stones tend to be the most expensive, followed by IGI. 
 
You can view a PDF sample of a GIA report below, along with their guide to understanding the report.

 

Click here for a printer-friendly version of the guide.

Should I buy a certified diamond?
 
This is entirely your choice. All of our lab-grown diamonds are certified, but we can source certified and uncertified natural diamonds depending on your preference. Whichever option you choose, we only source the highest quality diamonds from trusted UK suppliers, and carefully inspect each one on arrival. When you visit us to view a diamond, you can examine it using our 10x magnifier and compare the colour to our set of grading stones. 
 
If your budget will stretch to a certified diamond, it does make sense to choose one. The report will provide an independent and unbiased assessment so you can buy with confidence. GIA has an excellent blog post on the benefits of choosing a certified stone. A report can also be useful in the event of any future insurance claims, as you have an exact record of the diamond you purchased. Some certified stones will have a laser inscription of the report number on the girdle, which can be used to prove ownership if it is ever lost or stolen. 
 
A word of caution: it's important to remember that the quality of a diamond doesn't change because it has a report. The fact that a diamond is certified does not automatically make it a better stone - you need to pay attention to the content of the report. We've rejected plenty of certified stones after inspecting them in person, despite them looking good on paper. This is particularly important in the case of lab-grown diamonds, which can be graded as D colour but can still have a coloured tint or brown streaking due to poor manufacturing processes. This is explained in this article from JCK. 
 
If you're choosing a Round Brilliant diamond, the grading for 'cut' will take into account the stone's proportions and if it's been graded Excellent or Very Good, you can be confident that it will have plenty of sparkle and fire. The gold standard would be a Triple X diamond, which is the term we use for a diamond with Excellent cut, polish and symmetry listed on its report. However, this only applies to Round Brilliant diamonds. No official 'cut' grading is given for Fancy Cut stones. The report will list the dimensions and grade the quality of the symmetry and polish, but it will not offer an opinion on the stone's ratio or proportions. These factors are just as important when it comes to sparkle. This won't be an issue if you're buying a diamond in person because you'll be inspecting it with your own eyes. But it's something to consider if you're planning to buy a diamond online rather than through a reputable 'bricks and mortar' jeweller.
 
What is the best diamond shape?
 
This depends on what you want from your diamond. If you want the best sparkle, the fire and brilliance of a Round Brilliant Cut are unrivalled. However, it is also the most expensive diamond shape. If you want a large stone on a budget, choosing a Fancy Cut such as Oval or Pear will give the appearance of a larger stone at the same carat weight, as the surface of the stone has a larger spread than a round stone. You can read more about this in '4Cs - Carat Weight' below.
 
How much does a diamond cost?
 
The cost of a diamond will vary greatly depending on the carat weight, specification, and whether it is naturally mined or lab-grown. There is no 'one size fits all' price guide, as there are so many variables. Our aim is always to source the best quality diamond for your available budget, whether this is £500 or £10,000. If you've had a quote for a diamond from another jeweller, we will try our best to match it.  

You can check prices for loose diamonds and complete rings on our Ring Builder site. Please note we currently only offer certified natural diamonds in the Ring Builder.

 

Lab-grown diamonds cost significantly less than naturally mined stones of the same specification, especially at 1ct and above. Even at lower carat weights, naturally mined diamonds tend to cost 4-5 times more than their lab-grown equivalents. 


We only supply the highest quality lab-grown diamonds, with the finest being 'Green Grown' diamonds from Green Rocks. These do tend to be priced slightly higher than standard lab-grown diamonds, but the quality is truly unrivalled and we believe they are well worth the additional cost. We usually have a selection of Green Rocks diamonds in stock and available to view. 

Do all diamond shapes cost the same?
 
The 'price per carat' of diamonds can vary greatly depending on the shape. This is because all shapes are cut from a rough diamond and the excess diamond is discarded as waste. Most people don't realise that a 'carat' of diamond relates to the weight of the stone, not the size. A 1ct diamond will weigh 0.20g regardless of the shape. Shapes that use less of the rough diamond are more expensive, as a larger rough diamond must be used at the outset. For example, a Round Brilliant Cut stone only uses 40% of the rough diamond but a square Princess Cut uses 80%. This means to create a 1ct stone, the square stone can start with a rough diamond half the weight. In theory, this should make the finished stone much less expensive. Unfortunately, things aren't always that simple! 
 
It's impossible to say exactly how much you can save on your diamond by choosing a different shape, as no two diamonds are exactly alike. If you looked at a list of GIA-certified 1ct Round Brilliant diamonds all with D colour, VS1 clarity and Excellent cut, you would expect them all to cost the same. But you would find them all priced differently, and there can be a surprisingly wide range. This makes it impossible to compare different stone shapes and calculate the exact 'saving' of one versus another. But in general, fancy shapes do tend to be priced lower per carat than Round Brilliant, especially at 1ct plus. Many also have the benefit of appearing larger on the finger. 
 
The availability of your chosen shape will also affect the price, as diamond prices are based on 'supply and demand' like any other commodity. Round Brilliant Cuts are more widely available than Radiant Cuts for example, so although they are considered the most expensive shape, you will find more round diamonds to choose from and therefore a wider range of prices. You could have dozens of Round Brilliant diamonds to choose from within your budget, but only three Radiant. This inevitably means that some of the round diamond options will be cheaper, regardless of them being the most expensive shape 'on paper'. 
 
How can I save money on a diamond?
 
There are several guaranteed ways to save money on a diamond:
 
Choose a lab-grown diamond: A lab-grown diamond will cost a fraction of its naturally mined equivalent. At weights under 1ct, you can expect to pay 4-5 times more for a natural diamond versus a lab-grown diamond of the same specification. At weights above 1ct, you can expect to pay 10-20 more due to the rarity of high-quality natural diamonds at larger sizes. See below for more information about lab-grown diamonds. 
 
Choose a lower carat weight: Dropping a fraction of a carat will lower the price with very little difference in appearance. The difference in width between a 0.75ct and 1ct square Princess Cut diamond is only 0.5mm. Once set, they would look virtually identical on the finger. Changing the stone shape can also help with this, as stones such as Oval, Pear and Marquise look naturally larger on the finger. 
 
Choose a different grade: You can reduce the cost of your diamond by choosing a lower colour or clarity grade. For example, dropping from a D to F colour on a 1ct lab-grown diamond will save around £100. Although this example is a relatively small saving, if you're buying a naturally-mined diamond the difference could be several thousand pounds. 
 
Choose an alternative: If you have a very tight budget, we can offer moissanite as an alternative to lab-grown diamonds. The finest quality Charles & Colvard Forever One™ moissanite would be priced at roughly half the cost of the standard lab-grown diamonds shown in the table above. Download the Forever One™ brochure for more information.

 

You can also read more about moissanite in our blog post: The Truth About Moissanite.
 
What is a lab-grown diamond?
 
Laboratory-grown diamonds are formed using technology rather than geology. The only difference between lab and natural stones lies in their origin. Lab-grown diamonds are like ice from your freezer, while natural diamonds are like ice from a glacier. The ice from each has a different origin, but it is still ice. 
 
There's no doubt that naturally mined diamonds have an air of romance about them, as you're wearing something that is millions (or even billions) of years old and has been pulled from the earth. But if you're not sentimental about such things, a lab-grown diamond will give you an identical look for a fraction of the cost. Just like natural diamonds, lab-grown diamonds come in every shape, size, colour and clarity. The cutting and certification methods are identical for both. 
 
When at their highest quality, lab-grown diamonds are chemically, optically and physically identical to stones that formed naturally and have been mined from the earth, and the only way to identify a premium lab-grown diamond is to analyze it in a laboratory. Of course, not all lab-grown diamonds are created equal. There has been an influx of poor-quality diamonds onto the market in recent years, which show discolouration and tinting from poor manufacturing processes. These diamonds are fairly easy to distinguish from natural diamonds with the naked eye, as explained in this article from JCK. For the highest quality lab-grown diamonds, we recommend 'Green Grown' diamonds from Green Rocks
 
You can read more about lab-grown diamonds from GIA and IGI.  
 
Are lab-grown diamonds cheaper?
 
A lab-grown diamond will cost a fraction of its naturally mined equivalent. At weights under 1ct, you can expect to pay 4-5 times more for a natural diamond versus a lab-grown diamond of the same specification. At weights above 1ct, you can expect to pay 10-20 more due to the rarity of high-quality natural diamonds at larger sizes. 
 
A downside to this is their poor resale value compared to natural diamonds. But if you don't plan to sell your jewellery in future, this wouldn't be an issue. And of course, you've paid less to begin with!
 
Are lab-grown diamonds eco-friendly?
 
Many people consider buying lab-grown diamonds because they believe them to be a more sustainable and environmentally-friendly option than naturally mined stones. However, beware of 'green-washing'. Many lab-grown diamonds are far from sustainable. It takes immense amounts of electricity to produce a lab-grown stone and most growers are based in countries that still rely heavily on fossil fuels and produce vast greenhouse-gas emissions. So don't assume that your diamond is 'eco-friendly' just because it was grown in a lab. 
 
If sustainability is important to you, choose a truly sustainable option from our supplier Green Rocks, who became the world's first sustainably rated diamond producer in 2020. Their 'Green Grown' Process produces the most natural-looking lab diamond available on the market today, and the quality of their stones is unrivalled. 
 
For a truly eco-friendly option, choose a recycled diamond. We can source antique and modern options. 
 
What is diamond fluorescence?
 
You will see Fluorescence listed as a characteristic on diamond grading reports. Fluorescence is the soft coloured glow emitted when an object is exposed to UV light, such as a black light in a nightclub. This is usually blue and can range from faint to very strong. Only 25-30% of diamonds show some level of fluorescence. Of those, only 10% would fluoresce strongly enough to negatively affect their appearance under UV light, and even fewer would show any level of fluorescence in daylight. You can read more about diamond fluorescence on the GIA website.
 
What is a treated diamond?
 
A small percentage of diamonds are treated in an effort to improve their colour or clarity, for example HPHT treatment to make them whiter or laser drilling to remove inclusions. Treated diamonds are priced lower than untreated equivalents. We don't supply treated diamonds unless you specifically ask us to source one to reduce the cost, and we would always source a certified stone to ensure the quality of the treatment. You can read more about diamond treatments on the GIA website
 
What is a diamond simulant?
 
Diamond simulants are stones that have a similar appearance to diamonds and are used in place of them in lower-cost jewellery. They are often used to add sparkle to silver jewellery. Examples of diamond simulants would be moissanite, cubic zirconia (CZ) and crystal. The cost of diamond simulants can range from pennies for small crystals and CZ, to hundreds of pounds for large high-quality moissanite. Lab-grown diamonds are occasionally referred to as 'synthetic diamonds', but they are genuine diamonds rather than diamond simulants. 
 
We can offer moissanite in place of diamonds for engagement rings and other jewellery. We only use stones from the Charles & Colvard Forever One collection. This is the highest quality moissanite you can buy, with a clarity and sparkle unrivalled by cheaper alternatives offered by other jewellers. We can supply stones in weights up to 3.60ct, and in the following shapes: Round Brilliant, Oval, Princess, Cushion, Emerald and Pear. 
 
Click here to read our blog post: The Truth About Moissanite

4Cs - Diamond Carat
 

Many people believe that a 'carat' tells you the size of a diamond. But it actually refers to the weight of the stone, hence the term 'Carat Weight'. One carat of diamond always weighs 0.20g regardless of the shape. Larger stones are much rarer than smaller ones, especially at the higher cut, colour and clarity grades. Therefore a single 1ct diamond will cost much more than five 0.20ct diamonds of the same grade. You might also hear diamond weights referred to as 'points' rather than carats. A full carat is 100pts, 0.50ct is 50pts and so on.
 
Customers often like a nice round number when choosing a diamond, for example 0.50ct, 0.75ct or 1ct. In addition, many desire a 1ct diamond as this has become synonymous with the 'perfect' engagement ring. For this reason, there is often a large price jump once the 1ct threshold is reached. Dropping a few points can shave hundreds of pounds off the cost of your diamond without any noticeable difference in size. The difference in width between a 1ct and 0.75ct Princess Cut diamond is only 0.5mm, despite the larger stone being 25% heavier. So as you can imagine, the 5% weight difference between a 1ct and 0.95ct stone would mean an imperceptible size difference. Despite the two stones looking identical when set, the 0.95ct stone would cost substantially less. The same can be said about all of the popular thresholds. Dropping a few points can make the difference between getting a VS2 or a VVS1 stone for your budget, without compromising on the overall look of your diamond. There's even a term for this in the diamond industry - we call it "buying shy".
 
The surface area of two stones can vary greatly even if they are the same carat weight. For example, a 1ct Round Brilliant Cut measures approximately 6.5mm, and a 1ct Marquise Cut measures approximately 10mm x 4.75mm. It's much like having a lump of clay - it can be moulded into lots of different shapes, but they would all weigh the same. You will often hear that fancy shapes such as Marquise 'face up' larger than Round Brilliant stones. This means that a larger surface area is visible when viewed directly from above (for example when set into a ring mount). When choosing a diamond, it is important to avoid stones that have been deliberately cut shallow to 'face up' larger, especially in the case of a Round Brilliant Cut diamond. This will affect the proportions of the stone, resulting in a poor cut and lack of sparkle (see '4Cs - Diamond Cut' below). 
 
The shape of a diamond also affects the 'price per carat'. This is because all shapes are cut from a rough diamond and the excess diamond is discarded as waste. Shapes that use less of the rough diamond are more expensive per carat, as a larger rough diamond must be used at the outset. A Round Brilliant Cut stone only uses 40% of the rough diamond, but a square Princess Cut uses 80%. This means to create a 1ct stone, the Princess Cut would start with a rough diamond half the weight, which generally makes the finished stone less expensive. Due to the large 'face up' size and lower price associated with fancy cuts, choosing a shape such as Marquise or Pear can be a great way of getting a more impressive diamond for your budget. Marquise diamonds are often considered to be more at home in antique styles, but can be given a modern twist by setting them horizontally rather than vertically.

 

4Cs - Diamond Colour
 

A diamond's colour is established using the GIA Colour Scale, rating the stone from D to Z. As you'll see from the chart below, diamonds graded D - F are considered 'Colourless' and G - J are considered 'Near Colourless'. Colourless diamonds are much more expensive than Near Colourless, especially at D grade. The distinction between each colour grade is so subtle that it would be invisible to the untrained eye. However, even an untrained eye would be able to see the difference between D and J colour stones when they are compared side-by-side.
 
When choosing a diamond, we recommend selecting the best colour grade that you can afford. This is especially true if you intend to set the diamond in white metal, where a tint of yellow would be more apparent. We would always recommend choosing a D-F colour in this case. If the diamond will be set in yellow or white gold, it is possible to select a G colour and still have it appear white in comparison. If you don't mind a warmer look to your diamond, selecting an H grade can reduce the cost significantly. But we would not recommend dropping much below this, as the diamond would begin to appear tinted.
 
There are other factors to consider when choosing a colour grade. For example, the colour of any other diamonds or gemstones you intend to wear alongside your new jewellery (even an I colour diamond would appear fairly white if worn next to a yellow Citrine). The standard of cut is also important. Two brilliant-cut diamonds can have the same colour grade but appear very different due to the amount of light (sparkle) resulting from an Excellent cut versus a Good one. Emerald and Asscher Cut diamonds use step-cut facets which aren't designed to sparkle in this way, so we would always recommend choosing a D-F colour for these stones.
 
When you visit us for a consultation, we'll show you examples of each colour grade and make a recommendation based on your specific requirements, to ensure you get the best stone for your budget. You can read more about GIA colour gradings by clicking here.

4Cs - Diamond Cut
 

The most important of the 4Cs! When we talk about 'cut' in terms of diamond quality, we're not talking about the overall shape of the diamond such as Princess Cut or Emerald Cut. Instead, it is the quality of the cutting process itself being assessed. Has the stone been cut to ideal proportions? Is it symmetrical? What thickness is the girdle? Are the facets well-cut and well-polished? How well does it reflect light? As a result of this assessment, the diamond will be graded according to the GIA Diamond Cut Scale, ranging from Poor to Excellent.
 
A diamond with a Poor grade will lack sparkle and appear very dull. This could be due to poor cutting or polishing technique, or the overall proportions of the stone. You should think of a diamond like a hall of mirrors, each one perfectly smooth and angled perfectly, bouncing light from one to another. A diamond which is too deep or shallow will not reflect light as it should, nor would one with poorly angled facets or rough surfaces. Each aspect needs to be perfect for the light to bounce around the diamond and reach your eyes, giving the intense sparkle and 'fire' a diamond is loved for. A diamond with an Excellent cut will have unrivalled brilliance and will appear naturally whiter and brighter due to the reflection of light. There is simply no comparison between a well-cut diamond and a poor one. For this reason, we always recommend choosing an Excellent or Very Good cut, and don't supply stones below this.
 
It's worth noting that only Round Brilliant diamonds will receive an official Cut grading on their report. This is because the GIA Diamond Cut Scale scale was designed for use with round diamonds and has not been adapted for other stone shapes, which are referred to as Fancy Cuts. However, all stone shapes will receive a grade for Symmetry and Polish characteristics, using the same Poor to Excellent scale. These are important to consider when shopping for a Fancy Cut diamond. There are also recommended ratios for fancy stones, which will vary depending on the shape. For example, the ideal ratio for a square Princess Cut stone would be a perfect 1:1. But in reality, most Princess Cut stones will be slightly off-square. Pear Cut stones are considered to have an ideal ratio of 1:50, meaning the stone should be twice as long as wide. But this is only a guideline and you may prefer a slimmer or wider stone.
 
You can read more about GIA cut gradings by clicking here. Scroll down to view our illustrated guide to the most popular diamond shapes.  

4Cs - Diamond Clarity
 

A diamond's clarity is established using the GIA Clarity Scale. There are 11 categories ranging from Flawless to Included. Flawless and Internally Flawless stones are incredibly rare and expensive at all carat weights, so would not usually be available for general sale. At the other end of the scale, Included diamonds are considered poor quality and wouldn't usually be offered in fine jewellery. Most diamond jewellery will therefore fall between VVS and SI grades. Extremely included stones are often sold as 'Salt and Pepper' diamonds.

 

To determine which clarity grade should apply to a diamond, the assessor will examine the stone under magnification to identify inclusions (internal) and blemishes (external). They will consider the size, number and location of the inclusions and blemishes, the type of each (feather, grain, needle etc), and how visible they are (for example dark-coloured inclusions will score worse than white ones). They will also consider the overall effect the inclusions and blemishes have on the appearance of the diamond. But ultimately, the clarity grading is only based on the opinion of the assessor, and the same stone could have received a different grading if it was assessed by someone else. GIA grades each diamond twice using different assessors, to ensure the most accurate result. This is why GIA reports are considered to be the gold standard of diamond grading. 

 

As diamond clarity is assessed using 10x magnification by a skilled diamond grader, it would be very difficult to see inclusions with the naked eye in stones of SI1 and above. Even a good SI2 diamond could appear 'clean' to the naked eye, especially if the stone is well-cut and has brilliant facets. A good amount of sparkle can hide even the largest inclusions! But the official grading will affect the value of a diamond greatly. There is a huge difference in price between VVS and SI stones. There will also be variations in the cost of stones at the same clarity grade, depending on the factors listed above (size, number, type and location of the inclusions). For example, you could have two stones both graded as VS2, but one could have a few more inclusions, or the inclusions could be slightly darker. Both would fall within the range of VS2, but one is obviously a superior stone and would be priced accordingly. Prices often overlap between grading levels and an excellent quality SI1 can be priced the same as a VS2. This is because the diamond merchant decides the price of every stone they sell, not the GIA. 

 

Generally, we would recommend choosing a diamond with a minimum grade of VS2 to ensure you get the best quality stone, but we can also offer SI1 stones if your budget doesn't stretch to this. If you're choosing a step-cut Emerald or Asscher Cut, we would recommend a clarity of VS1 or ideally a VVS grade, as the large open facets will show every inclusion or blemish. We can also supply IF (Internally Flawless) diamonds on request.

 

You can read more about 16 types of inclusion and 11 types of blemishes on GIA's 4Cs Blog. You can also read more about GIA clarity gradings by clicking here

Diamond Shape
 

Often you'll be drawn to a particular shape/cut of diamond from the outset, and will have a clear idea of what you want. This is great as it can narrow down your search, and help us to make suggestions during your consultation. But don't discount any stone shape until you've seen it in person! When you visit us, we'll show you our sample set which contains the most popular shapes and carat weights. You could be certain that you want an Emerald Cut, only to have the sparkle of a Radiant Cut catch your eye. Often adding some accent stones can completely change the look of the centre stone.
 
Scroll down for more details about the most popular stone shapes, including 360 animations. You can also read the GIA's Guide to Diamond Shapes
 
We've covered the ten most common stone shapes below, but diamonds come in all shapes. The GIA recently certified an Elephant shaped diamond! We can source most shapes including Trilliant, Baguette, Trapeizoid, Kite, Fan, Half Moon, Crescent, Star, Octagon, Hexagon, Pentagon.... the list is almost endless.
 
We can also source antique stones. There is growing popularity for reusing Old Mine Cut diamonds, which were cut between 1890 and 1930. While not as bright and fiery as the modern Brilliant Cut, these antique stones can look spectacular. They have a deeper and warmer sparkle, with a subtle glittering effect. This draws the eye deep into the stone, and they truly come alive in low light conditions.

Round Brilliant Cut

The Round Brilliant Cut diamond (also known simply as Brilliant Cut) is the iconic diamond shape, accounting for around 75% of diamond sales worldwide. It has 58 angular facets designed to ensure maximum light transmission, giving unrivalled fire and brilliance. Many other shapes use brilliant-cut facets, but no other shape offers as much sparkle as the Round Brilliant Cut.
 
The Round Brilliant Cut is a classic and elegant diamond choice that will never go out of style, lending itself perfectly to both modern and traditional styles. When choosing this shape, is it important to choose an Excellent or Very Good grade of cut to ensure maximum brilliance. 
 
You can read more about Round Brilliant Cut diamonds in this GIA blog post.


Cushion Cut

The Cushion Cut diamond (also known as Pillow Cut) has a square or slightly rectangular shape with curved edges. The ideal ratio for a square Cushion Cut diamond would be 1:1, but elongated versions are readily available which give a rectangular shape. There is no ideal ratio for these, as it depends entirely on shape you prefer. There are various styles of Cushion diamonds, with the most popular being the modern 'Modified Brilliant' as shown below. This has additional facets to give a crushed ice effect and provide extra fire and brilliance, which can help to disguise inclusions. If you want a more vintage appearance, you could opt for a 'Standard Brilliant' or even an antique stone. 
 
The Cushion Cut was the most popular diamond shape until the early 1900s. It was known as a Candlelight Diamond, as the cut was designed to give the best sparkle in the candlelight used at the time. It is perfect if you want a romantic vintage look, or just want something a bit different to a round cut without opting for an angular appearance.
 
You can read more about Cushion Cut diamonds in this GIA blog post.


Asscher Cut

The Asscher Cut diamond (also known as Square Emerald, Square Octagon or Royal Cut) has a square shape with clipped corners. The clipped corners and stepped facets give it a similar look to the traditional Emerald Cut diamond, but it is often considered to be a more practical choice due to its compact shape. The ideal ratio of an Asscher Cut stone is considered to be 1:1, which gives the appearance of a completely square stone. Elongated versions are also available, which are slightly rectangular. The 72 step-cut facets used in the Asscher Cut create a stunning prismatic optical illusion called the 'Hall of Mirrors', drawing the eye to the centre with beautiful symmetry and clarity. This gives striking flashes of light from within the stone, rather than the intense sparkle given by brilliant-cut facets.
 
This style of cut was introduced in Amsterdam during the Art Deco period, making it a popular choice for vintage-style rings. However, the geometric shape and clean lines make it equally striking in modern designs. Due to the open step-cut facets used in this shape and the lack of distracting 'dazzle', it's important to choose a stone with excellent colour and clarity. We would recommend a clarity grade of VS1 or above, with a colour of D-F. If your budget doesn't stretch to this, consider a Princess Cut stone for a similar look. 
 
You can read more about Asscher Cut diamonds in this GIA blog post.


Square Princess Cut

The Princess Cut diamond (also known as Square Cut) has a square shape with sharp corners and a large table. It is a relatively modern cut, introduced in the 1960s. Being a square stone, the ideal ratio of a Princess Cut is roughly 1:1, and to be called 'square' it cannot exceed 1:1.05. However, rectangular Princess Cuts are also available which can have a ratio of up to 1:1.25. The 76 brilliant-cut facets provide fire and brilliance, resulting in much more sparkle than seen with the 'Hall of Mirrors' effect in the Asscher Cut listed above. The two cuts give a similar look, so Princess Cut could be a good option if your budget doesn't stretch to the colour and clarity recommended for an Asscher Cut stone. The intense sparkle provided by the brilliant-cut facets of the Princess Cut can help to disguise inclusions, and will naturally make the diamond appear whiter due to the way they reflect light.
 
The geometric shape and clean lines of the Princess Cut are perfect for providing a minimalist, contemporary look. The sharp corners must be protected with a suitable setting to avoid chipping. Box claws are an excellent way to protect the corners while retaining the angular look of the stone. Alternatively, it can be set with corner claws to give a similar appearance to the Asscher Cut, or protected with a halo setting. 
 
You can read more about Princess Cut diamonds in this GIA blog post.


Oval Cut

The Oval Cut diamond has a similar structure to the Round Brilliant Cut but has a flattering elongated shape. The ideal ratio of an Oval Cut stone is considered to be between 1:1.3 and 1:1.6, but this depends on personal preference as you might prefer a wider or slimmer stone. The 57 brilliant-cut facets provide fire and brilliance which can help to disguise inclusions.
 
The shape lends itself well to modern and classic styles, and it can be set vertically or horizontally. As the surface of the stone has a wider spread, an Oval Cut diamond will appear larger than a Round Brilliant Cut stone of the same carat weight.  
 
You can read more about Oval Cut diamonds in this GIA blog post

Marquise Cut

The Marquise Cut diamond (also known as Navette) has an elongated boat shape with pointed tips. It dates back to the 18ct century when King Louis XV of France requested diamonds be cut to resemble the lips of his mistress, Marquise de Pompadour. The ideal ratio for a Marquise Cut is considered to be between 1:1.85 and 1:2, but this depends on personal preference as you might prefer a wider or slimmer stone. The wide, shallow spread makes the Marquise Cut appear larger than others of the same carat weight. The 58 brilliant-cut facets provide fire and brilliance which can help to disguise inclusions.
 
The Marquise Cut can be set vertically or horizontally and is equally suited to classic and modern styles. It is important to choose a setting which protects the pointed tips of the stone to avoid chipping. A combination of box and standard claws is commonly used, along with bezel and halo settings.
 
You can read more about Marquise Cut diamonds in this GIA blog post.


Pear Cut

The Pear Cut diamond (also known as Teardrop) is another modified brilliant-cut stone with a rounded base and pointed tip. The ideal ratio of a Pear Cut stone is usually considered to be between 1:1.5 and 1:1.75, but this depends on personal preference as you might prefer a wider or slimmer stone. The 58 brilliant-cut facets provide fire and brilliance which can help to disguise inclusions.
 
Dating back to the 15th Century, the teardrop shape is still popular today and is often used for pendants and earrings. It also makes a stunning ring, and can be worn with the tip pointing upwards or downwards depending on your preference. It is important to choose a setting which protects the pointed tip of the stone to avoid chipping. A combination of box and standard claws is commonly used, along with bezel and halo settings.
 
You can read more about Pear Cut diamonds in this GIA blog post


Heart Cut

The Heart Cut diamond is a modified brilliant-cut with 56 to 58 facets, curved sides and a pointed tip. Considered the ultimate symbol of love and friendship, the Heart Cut diamond was introduced in the 15th century and remains popular today. The ideal ratio for a Heart Cut stone is considered to be between 1:1 and 1:1.2. It is important to choose a stone with perfect symmetry and a distinct cleft to ensure the heart shape is recognisable. This shape tends to work best in larger sizes, as the heart effect is lost on smaller stones. 
 
If you choose a Heart Cut diamond, it is important to choose a setting which protects the pointed tip of the stone to avoid chipping. A combination of box and standard claws is commonly used, along with bezel and halo settings.
 
You can read more about Heart Cut diamonds in this GIA blog post.


Emerald Cut

The Emerald Cut diamond (also known as Octagon or Step Cut) has a rectangular shape with clipped corners. The ideal ratio of an Emerald Cut stone is usually considered to be 1.40, but this depends on personal preference as you might prefer a wider or slimmer stone. The 57 step-cut facets used in the Emerald Cut create a stunning prismatic optical illusion called the 'Hall of Mirrors', drawing the eye to the centre with beautiful symmetry and clarity. This gives striking flashes of light from within the stone, rather than the intense sparkle given by brilliant-cut facets.
 
As the name suggests, this cut was originally designed for emeralds, but it has been used for diamonds since the 14th century. It is an excellent choice for antique-style rings, but the geometric shape and clean lines make it equally striking in modern designs. It can be set vertically or horizontally depending on your preference. Due to the open step-cut facets used in this shape and the lack of distracting 'dazzle', it's important to choose a stone with excellent colour and clarity. We would recommend a clarity grade of VS1 or above, with a colour of D-F. If your budget doesn't stretch to this, consider a Radiant Cut stone for a similar look. 
 
You can read more about Emerald Cut diamonds in this GIA blog post.


Radiant Cut

The Radiant Cut diamond was designed by Henry Gossbard in 1977. He created a new cutting method to combine the best elements of Emerald and Round Brilliant diamond cuts. The Radiant Cut is usually rectangular with an ideal ratio of approximately 1:1.25, but square stones are also available which have a ratio of roughly 1:1. The cut has clipped corners, paired with 70 brilliant-cut facets to provide stunning fire and sparkle. This gives an entirely different look to the 'Hall of Mirrors' effect created by the step-cut facets of the Emerald Cut, but retains the same overall stone shape. A Radiant Cut stone would be a good alternative if you like the look of Emerald Cut but want more sparkle, or don't have the budget for the colour and clarity recommended for step-cut facets. The intense sparkle of the Radiant Cut can help to disguise inclusions, and will naturally make the diamond appear whiter due to the way the brilliant-cut facets reflect light.
 
Radiant Cut stones can be set vertically or horizontally depending on your preference, and work equally well in modern and classic designs. This cut is particularly stunning when used with coloured diamonds.
 
You can read more about Radiant Cut diamonds in this GIA blog post.

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