This page is for people who want information about diamonds, about what makes them valuable and special, and how we decide which diamonds we want to buy and how to make sure we get the best deal.

What are diamonds

Diamonds are a form of carbon that were created under intense heat and pressure , millions of years ago, deep beneath the earth's surface. Today we use them in jewellery and many industrial processes. In industry they are used mostly for their hardness in tools that cut or grind, but how they came to be used in jewellery is a more interesting and nuanced story. Hardness and durability are definitely part of the story but why we give diamonds as gifts, see them as valuable and how they come to be turned from rough looking pebbles into strikingly sparkly gemstones is a much more human tale.

As remnants of our geological past diamonds can offer a window into processes that were going on deep beneath the surface of the earth millions of years ago. In 2022, researchers from Purdue university published a paper in the journal nature that described and analysed the inclusion in a diamond from Botswana.

Diamonds are the most well known, heavily promoted and mythologised gemstone in the world. The diamond industry spans the globe with every continent on the planet having a diamond industry of some kind. The only continent where there are no known diamond deposits is Europe.

Here we look at some of the common questions people have about diamonds and point you in the direction of further research and useful links and resources. Weather you are looking to buy, sell or just learn more about diamonds we can help and you are welcome to reach out for more information.

Are diamonds rare?

Yes and no. There are millions of diamonds here on earth but most of them are miniscule, much less than a 1mm in size and deep, deep the earth's surface. In this video, science youtuber Nile red vaporizes diamonds using pure oxygen and heat. The diamonds used in experiments like these are less than half a mm in size and most of the diamonds on earth are smaller than this.

The diamonds we use in jewellery are mostly 0.7mm +. A 0.25ct diamond is 4mm, a 0.50ct diamond is 5mm and a 1ct diamond is 6.5mm in diameter.

Only 3-4% of the diamonds mined every year weigh more than 1ct.

As a percentage of the earth's mass, diamonds make up approximately 0.000167% (that's one six-millionth) and most of these are many kilometres deep into the surface beyond the reach of any known mining technology.

As the worlds population has increased from 2 to over 8 billion in the last 100 years, the amount of natural diamonds so compared to the amount of people who may want, and have the money to buy diamonds, their availability has decreased. In an economic sense this has made them more scarce though continued mining has meant that commercial availability has remained consistent.

If you are interested in exactly how rare a diamond is use can use our diamond rarity checker.

Why do people say, ‘a diamond is forever’?

The slogan "A Diamond is Forever" was created in 1947 by copywriter Frances Gerety for the advertising agency N.W. Ayer & Son. Commissioned by De Beers, the campaign aimed to revive diamond sales after the Great Depression by linking the stones to the concept of eternal romance. It is now considered one of the most successful advertising campaigns in history, fundamentally changing how the world views engagement rings.

For further reading, explore these resources:

The Atlantic: An analysis of the market strategy behind the slogan.
The New York Times: A profile on Frances Gerety and her lasting impact on the industry.

Can I resize my diamond ring?

In almost all cases yes. Diamonds are particularly resilient to heat and are in general very tough. Ring resizing are the most common type of jewellery repair and alteration and thousands of diamond rings are resized across the world every day.

For a more detailed guide to resizing diamond rings you can read our guide to which rings can be resized or visit our ring resizing blog.

Often how well the diamond has been set, which metal it is set into and how many sizes it needs to go up or down has the biggest effect and how quickly a ring can be resized and how much it will cost.

For those who want a while you wait service, we offer a ring resizing while you wait from £89 from our Bloomsbury based London workshop.

Where do diamonds come from?

Diamonds were formed deep beneath the earth's crust and at certain points, via volcanic eruptions they pushed through the earth's crust and made it up to the surface. There are around 6,500 sites worldwide where this is known to have occurred.

Of the roughly 6,500 occurrences only a few contain diamond deposits that are commercially viable through mining and it is from these sites that the diamond we use today come from.

It's well known that many countries in Africa produce diamonds, with 15 countries on the continent producing diamonds. I visited Namibia in 2015, a country unique in that all of its diamonds are mined offshore in the worlds only marine diamond deposit. There are also significant deposits in Canada, Australia and Russia as well as smaller operations in Brazil, China, India and Indonesia.

Canada has always been associated with ethically mined diamonds and there has been extensive study and investigation in diamond mining Nunavut, Canada's largest and northernmost territory where its diamond deposits are located.

The best place to see a full list of diamond producing countries and where the deposits are located is Gemdat.org, an offshoot of mindat.org and open source mineral directory.

Can I break a diamond?

Yes. Diamonds are the hardest natural substance on earth but that doesn't make them indestructible. If a diamond has multiple inclusions or fissures then a diamond can crack along these lines if pressure is put on them.

If a diamond has a thin girdle, it may also be susceptible to cracking on impact with hard surfaces. Many gold diamond that were worn in jewellery will have small chip along their edge. If an older diamond it to be reset, then a rubover setting that covers the sides of the stone all the way around might be good way to protect these sides. (not all vintage diamonds are set with way to hide chips, but some definitely are)

What are brilliant cut diamonds?

The brilliant cut was developed and perfected polish diamond cutter Marcel Tolkowsky in the 1860/s and its purpose is to make diamonds sparkle as much as possible. ‘Brilliance’ is how jewellers describe sparkle and is not a superlative or a comment on the quality of the diamond.

The most common brilliant cut is the round brilliant which accounts for around 75% of finished diamonds worldwide. Other brilliant cuts are pear, marquise

How do I buy diamonds?

There are lots of ways for you to buy diamonds. In every town or city you will find jewellery stores selling diamonds already mounted into jewellery for you to buy. These stores might also allow you to purchase loose diamonds.

You can also buy diamonds online, mounted in jewellery or loose. When buying diamonds online you have a wider selection as many websites act as diamond aggregators, listing stones from vendors all over the world that they do not physically have in stock. You can view many detailed statistics about the stones but are not able to view them in person before purchasing.

When buying diamonds in this way you have access to vast numbers of stones and you are able to view and crosscheck their certificates. When buying diamonds in this way,

It is very difficult to buy loose diamonds wholesale. There is an extremely high barrier to entry for anybody wishing to buy loose diamonds in wholesale quantities and not just because you need a lot of cash. There are well entrenched supply systems and special custom restrictions for those wishing to import and export rough diamonds especially and polished diamonds also come with their own restrictions and reporting requirements.

What is a D colour diamond?

A ‘D’ is the highest grade on the diamond colour grading scale and a diamond that achieves this grade is devoid of colour. These diamonds are exceptionally rare.

What is a diamond certificate?

A diamond certificate is a document, produced by a laboratory, that describes the physical characteristics of a diamond. A certificate is an important document with helps to determine and add value to a diamond. The certificate itself does not describe a value as the value of a stone can change with fluctuations in the market. However, to anyone trying to asses the value of the stone the certificate will contain useful information.

Not all certificates are made equal with certificates from the GIA carrying the most weight. The GIA is the industry standard and if a stone has been certified by the GIA it will add to its value. Known for its consistently rigorous standards the GIA is headquartered is Carlsbad, California and has a strong preference towards natural gemstones,

The IGI, International Gemmological Institute is the next best well known gemstone laboratory and is much more focused towards lab grown diamonds. The IGI has 31 laboratories worldwide and has leaned into the growth of the lab grown diamond sector, offering comprehensive lab grown diamond grading reports and certification.

How much does diamond certification cost?

A full diamond dossier report from the GIA, for a 1.00 - 1.19ct diamond will cost $119. How much a diamond report cost depends on the size of the stone and the GIA’S Fee schedule outlines the costs involved in having your diamond graded and certified in one of their laboratories.

The IGI fees are listed on their submission form. You may only submit a diamond to be graded by the IGI if you have a DMIA member number

If you are submitting a diamond to be graded then the cost to have this done will range depending on the size of the stone and weather it is loose or mounted. If you are buying a diamond either loose or mounted in jewellery at retail then the diamond will often come with a certificate and the cost of certification is included in the price of the stone.

Non trade members can register with the GIA and submit stones for reports themselves however most people opt to do this through a jeweller who is already registered and can help with secure and insured transit to the laboratory.

Labs like the GIA and IGI interact mostly with the jewellery trade and not the general public.

How much do diamonds cost?

Diamonds can vary wildly in size and quality and therefore value. Even after manufacturing, sorting and export an individual 0.7mm diamond could cost as little as $3 and the largest diamonds sell for multi millions.

There are tools that keep track of the average price of certain points for instance the price of a 1ct diamond is an industry benchmark.

In 2025 the average spend for a diamond engagement ring in the UK was between £1,500 - £3,00. This great tool allows you to see data on engagement ring trends from all around the world.

What makes a good diamond?

To an extent, this is up to you. Which diamonds you are drawn to is down largely to personal taste and there maybe a difference between what you see as valuable and what the market sees. This being said, there are various parameters and scales which we use to measure and asses diamonds and these are split into various sections, knows as the 4C’s

Colour - The diamond colour scale goes from D to Z and

Clarity - The size, frequency and location of visible inclusions, either spots, clouds, fissuses or needles that a stone has.

Carat - How much a stone weights. A carat is a measurement of weight and 0.2 of 1g

Cut - Not just the shape but also how the facets are algined, how symmetrical they are and how well they are polished.

Which of the 4 C’s is the most important?

No one of the 4 C’s is the most important, they all matter but many in the industry feel that there are some that have an outsized impact on a stone, and some that it's not worth paying a premium for.

Colour vs clarity

The colour covers the whole stone and is visible to the naked eye, at a glance in a way that microscopic inclusions are not . There is a level where inclusions become visible, Si1 or lower, but the difference between a VVS1 and a VS2 stone can be minimal yet you may pay a premium for the VVS1. It is my professional opinion that you are better off going for a high grade colour stone and comparing stones of different clarity grades to make a decision about weather this is important to you.

Why are diamonds valuable?

Diamonds are valuable because people have decided they are and in blunt economic terms, because there is demand. Value is always a push and pull between supply and demand and weather you think that supply is artificially restrained or not, it's undeniable that diamonds have always been and continue to be in demand.

Some of the earliest known examples of diamonds being given as gifts or to symbolize love come from ancient Indian cultures where the first diamond discoveries were documented.

In 2026 we are used to seeing a huge variety of colors and visual effects. Modern smartphone screens can display over 1billion colours and we are used to seeing moving images in the palm of our hands. But think back to being a medieval peasant, somebody who will have never seen their own reflection in a mirror, cannot afford expensive dyes and. Imagine the effect a glittering, possibly colourful and virtually indestible rock might have on you? Our fascination with diamonds and gemstones may well be a relic of our past but as a species, we do seem to be susceptible to visual effects.

Do diamonds hold their value?

Not all diamonds hold their value but some do and many increase in value over time. Small diamonds, what's known as melee, generally do not hold their value and in some cases its not worth taking the time to carefully extract these stones when melting down jewellery for melt value.

Larger, rarer diamonds have always held their value and many of the world's largest diamonds sit in safes and vaults, serving only as a store of value instead of being worn as jewellery. Some diamonds make such vasts sums when sold at auction that they make the news.

Natural diamonds have a much better chance at holding their value than lab grown diamonds. There is no limit of the supply of lab grown diamonds and frankly they have been churning them out by the million. This means that the market for lab grown diamonds is flooded and consumers can choose between millions of diamonds in all shapes, sizes and qualities at very competitive prices.

The rarer and more unique your diamond, the better chance it has of holding value. Rarity and quality go hand in hand. For instance a flawless diamond is the best quality grade you can get for clarity and these stones are extremely rare.

Can I insure my diamond and jewellery?

Yes, diamonds and jewellery are commonly insured and it is advised that you do so.

Should I get a diamond engagement ring?

There are emotional and practical reasons why people get diamond engagement rings. On a practical level, diamonds hardness makes them ideal for a piece that gets daily wear and tear. Most people wear their engagement rings all day every day and with diamonds you can do this without damaging the stone.

What is the best cut of diamond?

Again, this is subjective and can be subject to trends. Old cuts diamonds are having a moment in the sun. Diamonds dealers around the world are rejoicing as stones they may have had in stock for decades are now flying out of the vault. This is in no small part down to Taylor swift and other celebrities who have

The ring that Travis Kelce proposed to taylor swift with featuired an 8-10ct elongated old cut cushion shaped diamond and.

Brilliant cut diamonds maximize performance so if you want your diamond to dazzle people from across the room then a really well cut, round brilliant cut diamond is the best choice. Other diamonds emphasise shape and if you feel that a certain shape of diamonds suits your finger well then that is the best shape to go for.

Step cuts have fewer, but larger individual facets meaning they can look quite open and large inclusions are easy to spot.

Where can I sell diamonds?

If you have a diamond to sell then there are a few options for you. Everybody wants to get the highest price they can when selling a diamond but as they are usually higher ticket items they can be slow to sell, especially if you are holding out for the best price.

As there is no VAT on secondhand goods, buyers will be expecting at the very least a 20% discount from retail prices with others looking for a lot more. The most prolific buyers of diamonds are the jewellery trade, and people in the jewellery trade will be buying diamonds looking to sell them on at a profit so may offer quick cash but drive a hard bargain.

If you are willing to hold out for a better price and do the work of taking good photographs, styling and listing your diamonds yourself then Auction or resale websites are the best way to achieve the highest price. Having a diamond grading certificate from either the GIA or IGI will help you to sell your diamond. If you can take picture of the laser inscription on the girdle of the diamond to prove it matches the certificate you have this will also help. As this inscription is tiny it might require specialist equipment like a good quality camera with a macro lens.

Auction sites - Well known, mass market auction websites like ebay can be great avenues for selling diamonds. Their mass appeal means they are frequently visited and to an extent trusted. eBays size and reach make it the best known but there are other, more specialist auction sites for luxury goods. Vinted, Etsy and Facebook marketplace are more market places than auction sites but all have categories for jewellery sales. Though except for etsy, these aren't well established avenues for diamond sales.

Physical auctions - Auction houses can be especially good for high value diamond sales. Well known names in this field have an established customer base, great PR and frequently achieve good prices for larger stones.

Sothebys and Christies dominate the list of the 30 most expensive diamond sales of all time and other houses such as Bonhams have well regarded jewellery departments.

Local auction houses will also offer jewellery sales and are a great avenue for selling lower value diamonds and the larger houses can be quite selective about the items they accept. For the US market, invaluable.com offers and A-Z of auction houses and in the UK, mbe.co.uk has a best auction house directory.

All auction houses take a commission on the final sale price and are incentivised to realise the highest price for your goods.

Pawn shops

Cash for gold - Businesses that primarily buy gold to be sold to refiners might also buy, gemstones though this isn't their primary area of expertise.

Sale or return - Local jewellers will often agree to sell your item on a commission basis, putting it in their window, earning a commission if your item sells. This can be a long term game but involves little risk to you, other than the item not selling.

The drawback of this approach is that jewellers will have little incentive to promote your time above their own. Even though the commission they earn is pure profit, they might prioritize the cashflow boost selling an item in its entirety brings.

Resellers - Specialty luxury resale websites will buy diamond and finished jewellery for resale. Xupes a Bishops Stortford based company operate a sell or exchange programme for luxury items including diamonds and jewellery.

What happens if my diamond cracks or chips ?

If your diamond does crack or chip then there isn't much that can be done to repair it. Most chips happen around the edges of a diamond as this is the thinnest point. To repair this a diamond can be recut but this reduces the overall weight of the diamond and therefore its value.

It might be worth reducing the weight to cut rid of a chip but often it isn't worth the expense of the having the diamond recut to remove small chips or scratches.

If a diamond breaks into separate pieces there isn't anything that can be done to repair it and the diamond will need to be replaced. If your jewellery is properly insured then this will be covered by your insurance.

Diamonds