In 2019 alone, there were thought to have been 142 million carats of diamonds mined around the world in places as far-flung as Canada, South Africa, Russian and the Democratic Republic of Congo.

Don’t worry, though, there are plenty left.

Estimates by MIT suggest there could be as much as a quadrillion tonne of diamonds between 90 and 150 miles below the Earth’s surface.

There are several reasons why people buy a diamond. They’re still the perfect gift for that special occasion such as a wedding or birthday. They’re also hard as nails which make them essential in modern manufacturing.

And, of course, for a narrow category, they’re also bought for investment for those who can afford it.

This article looks at what you should focus on when buying a diamond on your high street, online or from a dealer.

5 Diamond Facts

  1. A diamond is more than a billion years old and is the hardest natural substance on Earth.
  2. Despite their complex arrangement of its atoms, diamonds are made up of just one element, carbon.
  3. Diamonds are often thought of as off white/yellow or silvery but they can come in lots of other colours including blue, green, red and even black.
  4. There has been a planet called Lucy identified in the solar system that is thought to be at least one third made up of diamonds.
  5. The most expensive diamond in the world is called the Blue Moon which was sold in 2015 for a staggering $48 million.

The Diamond 4Cs and Why They’re Important

If you’ve never shopped for a diamond before, the first thing you need to understand is the concept of the 4Cs:

  • Cut
  • Colour
  • Carat
  • Clarity

These are essentially the characteristics that together define the quality of any diamond you buy on the high street today. These are not separate elements, either. Each diamond is different and these characteristics will vary from stone to stone. Whether you get value for money depends on how these balance out to create a ‘whole’ and it can often mean a trade-off here and there.

The 4Cs were introduced by the Gemmological Institute of America (GIA) in the 1930s and 40s to bring uniformity to the marketplace. Before this, judging a diamond was largely inconsistent and subjective. The grading allowed professionally trained jewellers to make more meaningful evaluations and this system is used to this day.

The Diamond Cut

When they are first dug out of the ground, diamonds resemble water-worn quartz. It’s not until they are cut that they begin to form into the brilliant jewels that we know from wedding rings and necklaces.

The person who does this is called a lapidary and they use a motorized circular saw to cut and shape the diamond. This is a highly specialized profession and requires the gem cutter to be able to spot flaws and which direction to cut for the best possible effect.

Defining the cut is probably the most difficult part of assessing a diamond and takes many years of experience. There are three effects that the cut helps to create:

  • Brightness: This is how much white light is reflected from the diamond, both internally and externally.
  • Fire: This happens when the light is scattered and creates colours of the rainbow.
  • Scintillation: This is how the stone glitters and produces the sparkle that we associate so much with diamonds.

When cutting a diamond, the lapidary has to make a trade-off between the cut and the weight of the stone so that it is shown off ‘in the best light’ while still maintaining value.

If someone is trying to maintain a high carat weight they may reduce the amount of cutting. On the other hand, a diamond that is cut to produce the optimum light reflection may well need to lose some of its carat value.

Cuts are graded as to whether they are ideal, excellent, very good, good, fair and poor and most of this is down to the skill of the gem cutters themselves.

Compared to the other Cs, the cut is the biggest indicator of a diamond’s beauty and often takes precedence when making an assessment. A designation of ‘excellent’ however doesn’t always mean that the diamond has the perfect cut.

You can see why this can be a difficult area to get right when you’re searching for the perfect diamond and it’s a good idea to have a professional take a look at the gemstone you are thinking of buying.

The Diamond Colour

Diamonds in natural light can vary between being colourless to slightly yellow and the GIA use a system of notation from D (clear) to Z (yellow or brown tint). The differences between each grade are very small and difficult to ascertain with the naked eye. This does, however, affect the value of the diamond.

Diamond colour is generally judged in conjunction with the setting that the diamond is being placed on. Another thing you need to be aware of is potential tinting, where other colours interfere with the white reflection and can detract from the sparkle. If you are buying a coloured diamond, however, these are graded slightly differently.

The Diamond Clarity

Natural stones can have a range of blemishes and imperfections such as inclusions and this affects their clarity. The GIA rates stones from flawless to included. An inclusion is any characteristic that interferes with the light passing through the diamond.

Very, very few diamonds are flawless and they are the most expensive so you should expect the ones that you buy on the high street to have some form of inclusion. If you are searching for a diamond, it’s good practice to look for ones that don’t appear to have any inclusions if you examine them with the naked eye. The simple fact is that the more obvious a flaw is, the less likely the stone is going to be of good quality.

The Diamond Carat

Carat does not refer to the size of the diamond but the weight. A 1-carat diamond weighs around 200 milligrams and a 5-carat diamond will weigh in the region of a 1.0 gram. While you might think that the higher the carat, the better the stone, this is not exactly true.

The quality of the stone itself and it’s cut is just as important, if not more so. For example, you might find a 1.5 carat stone that is fairly mediocre in quality and pales in comparison to a high-quality cut diamond that is only 1-carat. In other words, you can often be better off choosing an excellent cut stone rather than one that is a higher weight.

What is Diamond Fluorescence?

Another thing you may wish to consider is fluorescence. If you shine a UV light on a diamond it will sometimes emit a soft bluish glow. It’s seen as a defect in higher quality diamonds but actually around a third of stones will have this issue to some degree.

Unless you are planning on buying a diamond that is between D and H on the GIA colour scale where there is not enough body colour to counteract the fluorescence, it shouldn’t be a problem. For other diamonds, the effect is so negligible that it can make little or no difference and, in certain cases, can enhance the stone.

Most diamonds from reputable dealers should come with a fluorescent scale of between very strong, strong, medium and faint.

What is a Diamond Certificate?

If you are buying an expensive diamond then making sure it has a certificate is important. This means an independent expert has examined the diamond and confirmed it is what is said to be. This gives you complete peace of mind that the gemstone you are buying has the cut, colour, clarity and carat that you expect.

There are three main certification organisations:

Buying a diamond is often an emotional undertaking, especially if you are purchasing it for a loved one for a special occasion. The purpose of the certificate is to give you quick and easy confirmation that you are buying the right gemstone.

Each certificate will vary slightly depending on who produces but most contain the same information. This includes the carat weight and measurements of the diamond, the shape and cutting style, the colour grade, polish, symmetry and finish.

Not all diamonds come with certificates so you may have to get one done yourself if you are planning on buying. Diamonds that do have certificates are generally slightly more expensive and different labs like the GIA cost more than others.

The Cost of Your Diamond and Value for Money

The biggest challenge that new diamond buyers have is determining the real cost and whether they are getting value for money. This can be difficult, even for more experienced buyers. With such a substantial purchase, however, you want to make sure you get it right and aren’t overcharged.

The truth is that the cost of a diamond is influenced as other commodities are by who has been involved in the supply chain and what cut they have taken before the gemstone gets to the retailer and you.

Outside of this, the two big factors that affect price are the cut and the carat. A diamond that is 1 carat, for example, will cost about three or even four times a 0.5 carat one. The overall pricing is usually done across clear weight boundaries. So you will have 0.5, 0.75, 1.00 and so on which have their set prices. Finding a diamond that is either slightly above or below these values can therefore offer some savings without affecting the look and feel of the gem.

You might want to buy the biggest stone you can for your budget. If this is the case, you may have to compromise on the cut. Size is not everything when it comes to diamonds, however, and it’s important to buy something that looks good too. When buying, you will probably have to trade-off between different factors.

There is a huge difference in prices depending on the quality and cut of the diamond. A 0.5-carat gemstone could vary from as little as £500 to more than £3,500 depending on how the 4Cs come together.

The key here is to set your budget and look for diamonds that fit into this range. Working with a knowledgeable and approachable jeweller can save on a lot of hard yards.

Having Confidence in Your Jeweller

Picking the right jeweller is, of course, essential. If you’re looking for just the right diamond to buy, the person you are purchasing from must know what they are doing and understand the market. While buying online can seem convenient, it is fraught with problems when purchasing gemstones of any kind.

The first thing you want to be sure of is that your jeweller is listening to you. Picking a diamond ring for a wedding, for example, is a once in a lifetime undertaking and the setting of the diamond is just as important as the gemstone itself.

If the jeweller can’t answer your questions, then it can mean you are unsure whether the diamond you are buying is right for you. They should at least take the time to explain appraisals like the 4Cs and how you can get certification to ensure the diamond is as detailed if it is not already provided.

Most high street jewellers will have a range of diamonds that you can view and should be able to give you advice and guidance and, above all, give you the time and room to make your decision. With such an important purchase, taking your time and asking lots of questions can make a big difference and ensure that you end up with a diamond you can cherish for many years to come.



Diamond shape