What are Diamonds and Where do they come from?

We’ve all admired a sparkling diamond, but have you ever wondered where diamonds come from or what they are made of? Here is everything you need to know about diamonds.


Magical, elegant, and breathtakingly beautiful, diamonds have intrigued and captivated us for centuries. Whether they are set into stunning diamond rings or dazzling diamond jewellery, these iconic stones are widely recognised as a symbol of eternal love and commitment.

We’ve all admired a sparkling diamond, but have you ever wondered how diamonds are formed, or where diamonds are found? Or even, what are diamonds made of? Here, we’ll delve into the fascinating story of the world’s most adored and sought-after gemstone, answering these key questions, and many more.

How are diamonds formed?

So, how do diamonds form? Well, it might surprise you to learn that a diamond is made up entirely of just one element – carbon. A diamond results from the perfect combination of extreme heat and extreme pressure, which explains why most diamonds are formed 100 miles, or more, beneath the earth's surface. It's believed that temperatures of at least 1,000°C are needed to create the ideal environment for these precious stones to form.

People have long been intrigued by the question ‘how old are diamonds'? Geologists estimate the first diamonds were formed between 1 and 3.5 billion years ago, and that diamonds continued to form under the right conditions. Whilst there's no accurate method of dating any particular diamond, it's almost certain that any diamond will be at least several hundred million years old.

The colour of any diamond is influenced by trace elements present when it was formed, or by extremely high pressure. A yellow or slightly orange colour will reflect the presence of nitrogen, whereas a blue tint would be influenced by boron. The rarest, and therefore most coveted, diamond is colourless. It's unusual for a diamond not to be exposed to some form of trace element, hence the value of true colourless stones.

Today, all diamonds are graded using the four C’s - cut, colour, clarity and carat – which directly impacts each diamond’s value and are the barometers by which we judge the beauty and quality of each stone. However, a multitude of factors influence any gemstone's value, so the question 'how much are diamonds worth' unfortunately, doesn't have a straightforward answer. If you’d like to brush up on the four C’s, see our Diamond Buyers Guide.

Why are diamonds hard?

Known as being the hardest naturally occurring substance on earth, diamonds are as tough as they are beautiful. The extreme heat and intense pressure required to create diamonds, causes the carbon atoms to bond and crystalise and that’s what makes them so durable. Due to their hardiness and heat resistant qualities, diamonds have long been used for industrial purposes, such as drilling, cutting, and grinding. However, these diamonds are known as ‘rough diamonds’ and are a far cry from the dazzling beauties you’ll see set in luxury jewellery.

Where are diamonds found?

The first discovery of diamonds dates back to India over 6,000 years ago. However, diamonds have since been found in over 30 countries, including substantial volumes in Brazil, Australia, and China. Today the major diamond producers are predominantly located on the African continent, specifically, Angola, Botswana, the Democratic Republic of Congo, Namibia, and South Africa, as well as Russia and, most recently, Canada. Currently, Russia is the largest producer by annual carat weight, followed by Botswana and Canada, which is remarkable given that Canada’s first modern diamond mine was opened less than 25 years ago.

How are diamonds discovered?

Given that diamonds form way below the earth's crust, and far beyond the reach of any mining capability, how are they discovered at all? The answer is deep volcanic eruptions, the most recent of which occurred over 100 million years ago. These eruptions forced magma, or lava, toward the earth's surface, transporting diamonds with them like they were in a high-speed lift. When the lava reached the earth's surface it eventually cooled, and the diamonds were hidden within the igneous rock. These vertical, narrow channels of solidified magma have become known as ‘kimberlite pipes’. The name is taken from the town of Kimberley, where the 83.5 carat ‘Star of South Africa’ diamond was discovered in 1869.

How are diamonds cut?

Not all diamonds are suitable for use in jewellery. In fact, only around one in five are designated as gem quality. However, all diamonds start off as ‘rough diamonds’, a term that applies to a stone that remains in its original state. They often have an oily, dull appearance, an irregular shape and, to the untrained eye, they simply resemble lumps or shards of glass.

To reveal the brilliant sparkle of such a precious stone takes great skill and craftsmanship. The process of transforming a diamond from its natural state to the dazzling jewels we know and love can take several weeks or even months. A diamond that is expertly cut will capture and refract the light better, creating even more brilliance and sparkle. The measurements of cut quality include Brilliance (white light), Fire (colour), and Scintillation (sparkle).

The polished cut determines the shape, dimensions and finish of a diamond, and there are cuts available to suit all tastes. From classic brilliant round to feminine pear, or unique marquise, you’ll be spoilt for choice. As you'd imagine, the process of cutting diamonds has changed enormously over time, from planning by eye and then cutting by hand, to the state-of-the-art software that formulates 3D models for today’s gemcutters.

Are diamonds forever?

Despite their incredible durability, your diamond jewellery will benefit from a little TLC from time to time. When it comes to diamonds, grease and dust are the two most likely culprits for dulling their appearance. However, a quick wipe with a damp cloth or a specially designed jewellery wipe will help to keep the diamond sparkling and the settings clean. Another quick and easy method is to soak the jewellery in a bowl of warm water with a little washing-up liquid. You can even gently use a soft brush to help remove residue from hard-to-reach places. Once the jewellery is clean, give it a rinse in clean water then dry with a soft, lint-free cloth. When cleaning diamond jewellery, never use abrasive products or boiling water, as they could cause damage.

Regularly checking the claws and settings for any signs of damage is also important, especially for older jewellery or products that get a lot of wear. If you notice something that looks loose and you’d like to discuss repairs, or you need some additional cleaning advice, book a complimentary appointment at your local Ernest Jones store. You can even take advantage of the complimentary cleaning service we offer on items you’ve purchased from us. All you need to do is book an appointment and bring along your proof of purchase.

For more advice on keeping your diamonds looking their brilliant best, see our guide to jewellery care.

Discover diamond jewellery at Ernest Jones

As part of the world's largest diamond jewellery retailer, Ernest Jones is committed to responsible sourcing and only sells diamonds that are both conflict-free and ethically sourced - allowing you to shop with total peace of mind.

We are proud to exclusively bring you collections from some of the world’s most respected designers and diamond producers - including Vera Wang’s intricate and romantic range, Arctic Light’s virtually colourless Canadian diamonds, and The Diamond Story, where each ring comes with its own birth certificate showing your stone’s journey from a rough diamond to the glistening rock on your finger. From elegant diamond necklaces and bracelets to exquisite diamond rings and earrings, you’ll find a stunning collection of the very finest diamond jewellery at Ernest Jones.

We understand that shopping for diamond jewellery is a significant purchase. And we want to make sure you have all the information you need to help you make the right choice for you. If you have any questions, would like to discuss specific products or collections in more detail, or you’d simply like to pick our brains on the four C’s, enjoy a complimentary virtual or in-store appointment with one of our dedicated jewellery experts.