Lab Grown Diamonds

CVD Diamonds

CVD diamonds are identical to natural diamonds but made in the lab by Chemical Vapour Deposition. Learn how CVD diamonds are made, if and how they different to other lab and natural diamonds, and if a CVD diamond is right for you.

What is a CVD diamond?

CVD stands for Chemical Vapour Deposition, and is the commonly used name for diamonds grown in a laboratory via a process of chemical vapour deposition. This differs from another process commonly-used to create lab grown diamonds, HPHT (High Pressure High Temperature).

CVD diamonds are human-made diamonds, but are identical to natural diamonds and are 100% authentic diamonds. In fact, it is impossible to tell a CVD diamond apart from a natural diamond without specialist equipment. Learn more about lab diamonds vs natural diamonds.

Lab diamonds are becoming an increasingly popular choice amongst engagement ring and jewellery buyers - and along with HPHT, CVD is one of the most commonly used production methods. Some of the benefits of CVD diamond jewellery include ethical origins, sustainability, and cheaper prices- although you should be aware that CVD diamonds are typically lower quality than HPHT diamonds. As CVD diamonds increase in popularity, Queensmith’s gemmologists boast specialist expertise in the field of sourcing and selecting beautiful CVD diamonds for the best value for money.

Properties of a CVD diamond

CVD diamonds have the exact same properties as natural diamonds, possessing the same internal structure, chemical makeup and physical, lustrous beauty. Just like natural diamonds, CVD diamond properties include great durability, reaching 10 of the Mohs scale of hardness, and intense brilliance and sparkle.

While it is not possible to tell a lab-created CVD diamond from a natural diamond of the same quality, you should be aware that CVD diamonds often have less desirable traits, like brown tints and internal graining. This means they often require post-growth treatment. You will find HPHT lab-created diamonds are typically higher quality than CVD diamonds.

Just like natural diamonds, CVD diamonds are graded for cut, colour, clarity and carat weight. Whilst CVD are human-engineered, they are subject to the same flaws as natural diamonds, and can pick up colour tints and internal flaws while they grow. It is incredibly rare to find totally flawless CVD diamonds - some will be heavily included and poorly coloured, while others will be totally colourless, with only minuscule imperfections; just like natural diamonds. Look between SI1 and VS1 clarity grades, and D to F colour grades, for a diamond that appears top quality and provides value for money.

The reality is, even top gemmologists cannot tell a CVD diamond apart from a natural diamond. This is because CVD diamonds are diamonds, with the exact same chemical, physical and optical properties, and even the same flaws. When you buy a CVD diamond, its origin will be noted on the GIA or IGI certification. Other than this, you’d need specialist laboratory equipment to tell the diamond was human-made.

Chemical Vapour Deposition (CVD) diamond making process

  1. A thin diamond seed is selected and placed in a sealed chamber

  2. The chamber is heated to around 800°C and flooded with carbon rich gas

  3. The gas ionises, breaking down into pure carbon

  4. The pure carbon molecules attach to the original diamond seed

  5. This process continues until a fully formed diamond is created

CVD diamond creation requires a highly-specialised, scientific process that has been perfected over many decades, to produce jewellery-quality diamonds in an efficient and relatively speedy way. Chemical vapour deposition is a scientific process used to create a number of solid materials, often for use in the semiconductor industry - that has been adapted to create diamonds in two to four weeks.

A thin slice of diamond, around 300 microns thick and 10x10mm, known as a ‘diamond seed’, is selected and thoroughly cleaned. The diamond seed must be clean, as any trace elements or imperfections will be crystallised during CVD diamond growth, creating inclusions and blemishes. This diamond slice is typically taken from a high quality diamond created by HPHT.

The diamond seed is placed into a sealed chamber which is heated to around 800°C. The chamber is flooded with carbon rich gas. The chamber must be completely sealed, to avoid any other gases from entering and disrupting the diamond’s growth.

The carbon rich gas ionises under the intense heat, meaning its molecular bonds break down and settle on the existing diamond seed. The pure carbon molecules bond to the diamond seed, building and building as more gas ionises and bonds to the existing diamond. This crystallisation continues until a fully formed, rough diamond is produced, and the process is ended.

CVD diamonds are grown very quickly, which can cause less beautiful traits, like graining, spotty inclusions and brown tints. These can be removed or improved with a post-growth HPHT treatment. This improves the overall look of the diamond, but may causes milkiness. Therefore, its best to find a CVD diamond that hasn't undergone post-growth treatment! This will be mentioned on the diamond's certificate.

Following creation, a CVD diamond continues to have a similar journey to a natural diamond - it will be professionally cut to the required shape, and meticulously polished to produce optimal sparkle and brilliance. Then, the diamond will be graded and certified by independent laboratories like GIA and IGI, before entering the jewellery market to be traded by diamond dealers. Jewellers like Queensmith will scour the market to find the best CVD diamonds to show their clients, taking into account the diamond’s official certification, beauty and price.

How fast do CVD diamonds grow?

The speed of a CVD diamond’s growth depends on the end-goal size of the stone and the efficiency of the technologies used. Top CVD diamond producers can create 1ct diamonds in less than a month, and slightly smaller diamonds in as little as two weeks. Fancy colour diamonds, like yellow CVD diamonds, can take between 5 and 10 days, because the nitrogen added to create the yellow colour speeds up the crystallisation process.

CVD vs HPHT diamonds

An HPHT diamond is created using a process called High Pressure High Temperature, whereas a CVD diamond is created by using Chemical Vapour Deposition.

Instead of using gas, the HPHT process involves mimicking the natural diamond-making process where high levels of pressure and temperature within the earth create diamonds over millions of years. Similar to CVD diamonds, HPHT diamonds only take a few weeks to form, though this method does require higher levels of energy. Experts find that HPHT diamonds are typically created to a better quality than CVD diamonds and less frequently require post-growth treatment.

The main difference between rough CVD and HPHT diamonds is their formation. CVD diamonds grow into a cubic shape, whereas HPHT diamonds grow into a cuboctahedron. Only a carefully trained expert would be able to tell the difference, though.

You’ll also find that some labs start off with the less energy-intensive CVD process, before finishing off the diamonds with HPHT. This is because HPHT can help provide impressive clarity and colour, however, both CVD and HPHT diamonds are chemically, physically and optically identical to natural diamonds.

How do you identify a CVD diamond?

It is not possible to identify a CVD diamond apart from a natural diamond without specialist laboratory equipment and gemmological knowledge, because they are identical. Just like natural diamonds, CVD diamonds can be found in a range of qualities and grades - but compare two with the same grades and you wont see a difference. This is great news for CVD diamond buyers, who might otherwise worry that a CVD diamond could appear fake or different from a natural diamond.

Technically, when you look at a CVD diamond under magnification, you may be able to tell the diamond has different strain patterns to natural diamonds. It would require specialist gemmological knowledge to know what to look for, and even top gemmologists could struggle to see the difference.

Equipment can be used by diamond laboratories to tell if a diamond is CVD created, to look for minute trace elements like silicone, which could be picked up during creation. The knowledge and equipment needed is highly specialised, and you’d be required to submit your diamond to a laboratory like GIA.

When you buy a CVD diamond, make sure it is certified GIA or IGI. The accompanying certificate will outline whether the diamonds are natural or lab created via CVD or HPHT - and crucially, whether the diamond has required a post-growth treatment to get it looking up to scratch. Diamonds with post-growth treatments are best avoided.

CVD grading and certification

Just like mined diamonds, CVD diamonds are graded for their cut, colour, clarity, carat weight, and other details like their fluorescence, polish and symmetry. There are a number of grading labs across the world that certify lab diamonds, but the most renowned and trusted are GIA and IGI.

Both GIA and IGI assess CVD diamonds for their characteristics, to give an accurate reading of their quality, which then guides the pricing of the stone. GIA and IGI laser imprint a unique code on the girdle of the stone, only viewable under magnification, which corresponds to the paper (or digital) certificate, where you’ll find all the details of the stone, including the grades, carat weight and measurements. The certificate will also confirm if the diamond was created by CVD, HPHT, or if it is a natural diamond.

At Queensmith, we always advise you only buy lab diamonds certified by GIA and IGI. Every diamond we stock has been vetted and selected by our gemmologists for both value for money and beautiful aesthetics - and we only source GIA certified diamonds and IGI certified diamonds.

How much do CVD lab diamonds cost?

The price of a CVD diamond can be significantly less than a natural diamond. This is because CVD diamonds are created in a laboratory through an efficient process that typically takes less than one month. In comparison, natural diamonds take billions of years to form, and mining companies must invest a great deal of time and money to acquire land, excavate the land and build mines, and employ a large workforce. CVD diamonds require investment in specialist (expensive) equipment and a highly skilled workforce, yet the process is efficient and overall more cost effective than mining.

CVD diamond price vs natural diamond

Both CVD and HPHT lab diamonds are usually between 50% to 80% cheaper than natural diamonds. They are, however, still high-value items, and are a precious, valuable commodity that cost thousands of pounds. A lot of work and professional expertise goes into creating, cutting, polishing and grading a CVD diamond.

The future value of lab diamonds is not certain as they are relatively new to the market, and it is unclear whether they will retain value. Experts predict that lab diamonds will never be cheap, and will always be a significant investment as the HPHT and CVD processes require investment in high-level technology, expertise and time. Some even suggest the cost of lab diamonds could increase in the future as demand rises.

Compare lab diamond vs natural diamonds prices.

Is a CVD diamond right for me?

Actually, our advise is to choose a lab-created HPHT diamond over a CVD diamond; they are more consistently of a top quality and don't feature the signature milkiness of a post-growth treated CVD diamond.

The choice between natural vs lab diamonds is a more personal decision. To put the debate in plain terms, you’re choosing between a less expensive, guaranteed ethical and ecologically sustainable option (the CVD or HPHT diamond) versus a wonder of nature created over billions of years (the natural diamond).

Each of our consultants are trained and deeply knowledgeable about both lab grown and natural diamonds. To help you reach your decision, we can show you a range of the best lab vs natural diamonds for your preferences and budget. Get in touch to speak to our experts.

We’re here to help

We get it, you’ve never done this before.

That’s why we have diamond and design experts on hand, who are here to guide you through every step - from understanding what carat, color, cut and clarity mean, to designing the perfect ring.

Frequently Asked Questions

About Lab Diamonds

Making Lab Diamonds

How long does it take to make a lab grown diamond?

Lab diamonds typically form between 2 and 4 weeks. The process can be quicker if other elements are introduced, like nitrogen, but this can make the diamond yellow-tinted.

Do lab diamonds test as real diamonds?

Yes, lab diamonds test as real diamonds, because they are authentic and identical to those found in nature, with the exact same chemical makeup. However, specialist laboratory equipment can tell lab diamonds from natural diamonds.

Is it possible to make a lab grown diamond at home?

No - you’d need a great deal of specialist equipment to create a lab diamond, and it could be an incredibly dangerous process in the wrong hands. It takes a wealth of knowledge for trained scientists and engineering specialists to create a lab diamond - and it’s a very exact science in which the creator must work out the precise, perfect conditions for diamond growth. The intense heat and intense pressure that takes place during lab diamond creation isn’t something you can replicate at home.

Do lab grown diamonds come in different colours?

Yes, lab diamonds can be created in a number of fancy colours, including yellow, blue, pink, orange, green, red and black. In nature, trace elements enter the otherwise pure carbon diamond to cause colouration - like boron in blue diamonds, and nitrogen in yellow diamonds. The same idea can be applied to lab diamonds, where the scientist will work out the perfect amount of trace elements to add during the diamond creation.

Buying A Lab Diamond

Where can I buy lab grown diamonds in the UK?

Queensmith is one of the first jewellers to offer lab diamond rings in the UK.

The world of lab created diamonds is still relatively untouched by the UK engagement ring market, meaning there are few retailers where you can buy lab grown diamond engagement rings and jewellery. Queensmith is at the forefront of understanding and retailing lab grown diamonds alongside our bespoke engagement ring and jewellery services.

After learning your rough budget and an idea of what you’re after, our gemmologists will work on putting together a select range of the finest lab grown diamonds for your unique budget, before meeting with you to discuss your engagement ring or jewellery design.

Book an appointment online or in-store to meet with our diamond & design experts.

What’s the sentimental value of a man made diamond?

This one is up to you. Some adore the romantic history behind naturally grown diamonds, formed over billions of years, rare, precious and perhaps nature’s most beautiful and enchanting creation. Others prioritise the ethical value of lab grown diamonds, and praise the wonder of science in creating something it took the earth billions of years to do so. It’s the power of nature versus the wonder of science - which camp are you in?

Book to discuss with an expert.

How to choose the best lab created diamond for your ring

Choosing the best lab grown diamonds for your engagement ring is no different to choosing a natural diamond. If you’ve decided a lab grown diamond engagement ring is right for you, follow these steps:

  1. define your rough budget
  2. choose the ring style you like, and minus the cost of this to see how much you can dedicate to the diamond
  3. choose the shape of lab diamond you’re after
  4. consider diamonds graded Excellent cut (for round diamonds, or Excellent polish & symmetry for other shapes), D to F colour, VS2 to SI1 clarity

You can read more about choosing the best diamond for your engagement ring here, but the characteristics to prioritise are an excellent cut, followed by a high colour grade. This will ensure that a diamond appears bright, white and extremely sparkly. When narrowing down the options for your lab grown diamond engagement ring, it’s important to seek advice from qualified gemmological experts, to help you understand the intricacies and characteristics of each diamond, point out any flaws, and help you find the best value diamonds for your unique budget. For more advice or to receive a tailored quote, get in touch with our experts.

Can I insure my lab grown diamond engagement ring?

Absolutely. Just like any high value purchase you make, it is important to insure your lab grown diamond ring. The cost of insuring your lab grown diamond is likely to be less than that of a mined diamond, and your insurer of choice will most likely need to see a copy of your order invoice to verify the value of your insurance.

More About Lab Diamonds

Why are human-made diamonds called ‘synthetic diamonds’?

Whilst the terminology can seem a little confusing, man made, ‘synthetic diamonds’ are real diamonds - created in a lab. The term ‘synthetic diamond’ refers to the synthetic (i.e. human-made) environment in which a lab grown diamond is created.

Synthetic diamonds are not to be confused with diamond simulants. Diamond simulants are not diamonds, but are stones that are somewhat similar in appearance and are generally used for cheaper, high street jewellery, such as cubic zirconia and moissanites. Our gemmological advice is to steer clear of diamond simulants: they do not retain value, and more importantly are less striking in appearance, particularly their sparkle, lustre and crisp structure.

What else are lab grown diamonds known as?

Lab grown diamonds are referred to as synthetic diamonds, artificial diamonds, as well as man made, manufactured, lab created, engineered, cultivated and cultured diamonds. These terms all mean the same thing, but 'lab grown' is the term that is most commonly used by jewellers and jewellery buyers.

How long does it take to create a lab grown diamond?

Typically, lab grown diamonds take between one and two weeks to form. Compared to the natural process, which takes billions of years for diamonds to form and enter the Earth’s surface, it is an incredibly quick process!

CVD and HPHT Diamonds

Which is better, CVD or HPHT diamonds?

Most experts agree that HPHT diamonds are better quality than CVD diamonds. CVD diamonds are fast growing, which can cause spotty internal marks and graining. CVD diamonds are also known to have brown-ish undertones when produced, meaning they must undergo post-growth treatment to enhance their beauty. HPHT diamonds are typically produced at a higher standard, without the requirement for post-growth treatment.

Are CVD diamonds real?

Yes, CVD produces authentic diamonds. A CVD diamond is not artificial - it is 100% genuine diamond, identical in every way to the diamonds found in nature. You might hear some people call CVD diamonds ‘artificial diamonds’, but this refers to the artificial environment in which they are created, rather than the diamonds themselves being fake. It is a confusing term, which is why the industry is starting to abandon the phrase.

Are CVD diamonds treated?

Most CVD diamonds are treated after creation to enhance their clarity and colour grades. In comparison, fewer lab diamonds created by HPHT need such post-growth treatment to enhance their beauty. Having said this, some CVD diamonds are perfectly gem-quality when created, meaning they don’t need to be treated. This is the same with natural diamonds. You’ll see whether a diamond has been treated on its certificate.

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