How are Lab Grown Diamonds Made?

Lab-grown diamonds are the jewelry success story of the 21st century. From a mere 2% of all diamond sales in 2018 to 10% of all diamond sales in 2022, this movement has shocked the industry to its core.

As people become more aware of the bloody history of mined diamonds and that lab-grown diamonds hold the same visual qualities as those extracted from the earth, it’s no surprise that they have achieved mainstream success.

But how are lab-grown diamonds made? Here’s everything you need to know about the lab-grown diamond process.

How Lab-Grown Diamonds are Made

Today, China is responsible for 50-60% of synthetic diamond production, with India in second place. But are they technically diamonds at all?

Customers unfamiliar with manmade diamonds may wonder whether these diamonds are genuine. For this, we look to the Federal Trade Commission (FTC) definition:

The FTC defines a diamond as a piece of pure crystallized carbon with an isometric cube arrangement. Nothing more, nothing less. All references to “natural” were removed in 2018, indicating a win for the consumer vs. the mining industry.

With this in mind, how do you grow diamonds in a laboratory and still achieve the same results as a naturally-occurring diamond?

Diamond Seed Formation: The Initial Stage of the Growth Process

Can diamonds be made in a lab? They can because a diamond is nothing more than crystallized carbon. Laboratories replicate the conditions under which a natural diamond would be grown to create a gemstone with identical qualities.

The initial stage of the growth process begins by choosing one of two methods.

High-Pressure, High-Temperature (HPHT)

The HPHT method begins with a small diamond seed placed in a piece of carbon. A cubic, split-sphere, or belt press is used to apply pressure to the carbon to the tune of 1.5 million pounds per square inch.

Additionally, the carbon will be exposed to searing hot temperatures of more than 2,700 degrees Fahrenheit. Adding high pressures and temperatures will melt the carbon and form a diamond around the initial seed.

Chemical Vapor Deposition (CVD)

Less common but still prominent is the CVD method. So, how are lab-grown diamonds made with this method?

In CVD laboratories, a small diamond seed is placed inside a sealed chamber. In most cases, this diamond seed will be another synthetic diamond made using the HPHT method.

Within this chamber, the diamond seed is exposed to 1,400 degrees Fahrenheit and a selection of methane and hydrogen gases. The gases are ionized into a plasma to break the molecular bonds within the gas.

This method aims to get pure carbon to stick to the seed to form a brand-new diamond layer.

Growth Process: Creating a Diamond Layer by Layer

How long does it take to make a lab diamond using these methods?

Truthfully, it depends on the method and the type of diamond being grown. But while a natural diamond will take billions of years to form, lab-grown diamonds take less than a month to grow.

White diamonds are the purest, and so take the longest to grow. Regardless of the method, growing a single-carat can take two or more weeks, which is why white diamonds remain the most coveted. In contrast, blue and yellow diamonds take five to ten days.

With that in mind, building a diamond from a microscopic piece of material takes time. How the diamond grows depends on the method, so here’s how your diamond forms.

HPHT Growth

The HPHT technique produces more aesthetically pleasing results because it perfectly replicates the heat and pressure a naturally occurring diamond will experience.

HPHT diamonds are placed into a containment cube. The cube will then be pressed under the same pressure a diamond experiences under the surface of the Earth.

The carbon is heated to its ideal temperature with electric pulses. Over time, the heat and pressure causes the dull piece of carbon to crystallize. Once crystallized, you will notice a rough diamond within the containment cube.

Unlike natural diamonds, which come with four sides, HPHT diamonds emerge as cuboctahedrons with 14 sides.

CVD Growth

CVD diamonds are built up naturally by using a combination of heat and injected carbon-rich gasses.

Firstly, a laboratory will take a thin slice of a lab-created diamond. Typically, this is 10x10mm and just 300 microns thick. The diamond slice must be cleaned thoroughly before being inserted into the chamber, as any defects will grow with the diamond. Once ready, the diamond slice is injected into the chamber and sealed.

After being heated, the chamber will be flooded with hydrogen and methane. Laboratories will also add nitrogen gas to speed up the process if they value speed over quality. The downside of adding nitrogen is that it yellows the diamond, and yellow diamonds are less valuable on the open market.

The inserted gas will break down, which coats the diamond slice and forms a new chemical bond. Over a couple of weeks, gas continually breaks down and coats the diamond, increasing its carat weight.

When the process ends, the rough diamond will resemble a square cube.

Diamond Quality Control: Ensuring the Desired Characteristics

Knowing how are diamonds grown in a lab will also reveal that practically any type of diamond is possible with modern processes. However, this control also leaves little room for error.

For example, if either of the above processes is rushed, the crystal will fracture, leaving with laboratory with no alternative but to start again. Likewise, if a CVD diamond is grown from a slice with imperfections, those imperfections will be amplified within the new lab-grown diamond.

Both processes require rigorous quality control for temperature, pressure, and gas presence. Incorrect calibrations will result in the process failing to create a workable diamond at all.

But while all laboratories can be confident in the type of diamond, they can expect to emerge from the two growth processes, this is not the final step in forming a rough diamond. Getting the desired characteristics requires further treatments, which, again, depend on the growing method used.

HPHT Treatments

HPHT is the original method of growing diamonds in a lab. Since it closely replicates the conditions under which a natural diamond is formed, these diamonds emerge as colorless.

However, further heat treatments are required to reach the desired color and clarity. The choice of heat treatment will depend on the type of product. Here are three examples of different heat treatments:

  • Blue Diamonds – HPHT-grown diamonds will be treated using boron to create blue diamonds.

  • Green Diamonds – Adding a nickel heat treatment will turn an HPHT diamond green.

  • Pink Diamonds – Pink or red HPHT diamonds can be treated using radiation treatment to achieve different shades of pink/red.

Since coloring an HPHT diamond before cutting requires further treatments, these gemstones are significantly more expensive because of the extra work involved.

CVD Treatments

In contrast to their HPHT counterparts, CVD diamonds emerge from the chamber with brown or yellow colors. These diamonds are considered unsuitable for sale in most reputable jewelry outlets because of these imperfections.

To create white or colorless diamonds, standardized heat treatments are employed to remove these imperfections. But like HPHT diamonds, CVD diamonds can be treated with various gases to create pink, blue, and yellow diamonds.

Cutting and Polishing: Transforming the Rough Diamond Into a Finished Gem

With the optimal color and clarity achieved, the last step is to turn a rough diamond into a diamond suitable for sale. Now that you know how do they make lab-grown diamonds, how do they cut them for sale?

This is often the most in-depth part of the process because one mistake can ruin the value of a lab-grown diamond.

Step One – Sorting

Before cutting, the rough diamond will be analyzed and placed into various categories. The factors a team will incorporate include color, clarity, size, fluorescence, and model.

Occasionally, a small window of the diamond will be polished to help the planning team decide.

Step Two – Planning

The planning stage determines how best to cut a diamond to enable it to retain the most weight and yield. Remember, natural diamonds can lose up to 50% of their weight when cut and polished, so making the wrong cut can lose a significant chunk of the lab’s profit.

To mitigate this risk, planners will use technology, experience, and intuition to maximize yields while planning their cuts.

Step Three – Marking

Once a plan has been settled, the uncut diamond will be marked with a pen to show where the cuts should be made.

Step three is also where the team will decide whether to saw or cleave the diamond.

Step Four – Cleaving or. Sawing

Nearly all rough diamonds need to be divided to achieve the maximum yield. Cleaving is typically reserved for rough diamonds with cracks and fractures to eliminate them.

Cleaving involves dividing a stone by striking it with a sharp blade. Where the blade strikes depend on the lines of diamond growth, which is the cleavage plane. A small groove, known as kerfing, is made beforehand to ensure accuracy.

On the other hand, there is sawing, which can be done with a metal blade or a laser. This is the least preferable option because sawing a rough stone will result in more wastage and increase the risk of fracturing.

In all cases, cutting with a laser is preferred because stones lose far less weight than if metal blades are employed.

Step Five – Bruting

The bruting process is where the stone is shaped. This happens by cutting a diamond with another diamond. Until the start of the 20th century, a gem cutter would perform this process manually. Naturally, manual bruting leads to far less precise cuts, which is why older gemstones tend not to be perfect.

Power-driven wheel bruting machines took over from their manual brethren because they were more efficient and enabled diamond cutters to create perfectly round diamonds for the first time.

After a diamond has been through the bruting process, you’ll see that your diamond has its assigned shape, such as round, oval, pavilion, or girdle.

Step Six – Blocking

Blocking your lab-grown diamond means polishing its main facets using a Scaife. The Scaife is a polishing wheel using diamond powder or olive oil/graphite as lubrication.

This in-depth polishing process is also used to influence the shape of the finished diamond. If the pavilion section of the diamond is polished, it will form a culet. If the crown section is blocked, it will form a table.

Step Seven – Brillianteering and Quality Check

The final manual step is brillianteering. In short, this is the final polish where all of the facets of the cut diamond will be made to perfection.

Once satisfied, the finished diamond move to a final quality check. A team of gemologists will weigh the diamond and inspect every aspect. They will decide whether to accept the diamond for grading or return it for re-cutting or re-polishing.

After release from the quality control department, the diamond is submitted to a certification lab before being laser inscribed and released onto the market.

Why Choose Lab-Grown Diamonds?

Knowing how to make lab-grown diamonds and natural diamonds will undoubtedly make you think that the process is highly similar. And that’s because it is.

One of the primary benefits of lab-grown diamonds is that gemologists aim to match the natural conditions of a mined diamond while employing identical cutting and polishing techniques.

So, why should you choose a lab-grown diamond?

Lower Prices

How long does it take to grow a lab diamond? Around two weeks to a month. How long does it take to create a natural diamond? Billions of years plus the time it takes to find and mine them.

The production costs of diamonds have decreased dramatically because of the entry of lab-grown diamonds into the market. Miners find themselves being undercut by identical products produced at a fraction of the price.

According to the International Gem Society, a lab-grown diamond of similar size and quality can cost 50% less than a mined diamond.

More Ethical

Conflict diamonds remain a considerable problem. While a study in 2006 reported that just 4% of the world’s diamonds are conflict diamonds, this hides a sad fact.

These diamonds are classified under the Kimberley Process. Unfortunately, this hides a lot of the truth. According to Time Magazine, the definition of this process pertains to diamonds sold to fund a rebel movement seeking to overthrow the state. It does not cover any other circumstance, meaning the 4% figure is a massive underestimation.

Lab-grown diamonds don’t have this problem because they are always manufactured within state-of-the-art labs registered with the authorities, meaning you don’t have to wonder where your diamond originated.

Environmentally Friendly

Diamond mining is enormously bad for the environment. Carbon emissions from mining, tearing up the earth, polluting waterways, and demolishing the natural environment to make way for industrial operations are some of the ways that diamond mining harms communities and the planet.

The process of making lab-grown diamonds ensures that the footprint of the jewelry business decreases because of eco-friendlier processes.

It’s why some jewelers sell lab-grown diamonds exclusively.

Unrivaled Quality

In short, lab-grown diamonds enjoy the same high-quality finishes as natural diamonds. The difference is that because the conditions in which lab-grown diamonds are formed can be controlled, it’s possible to exceed the clarity and quality of a natural diamond.

While there are tools a professional can use to mark out a natural from a manmade diamond to the average person’s eye, there is no difference.

By choosing the more sustainable option, you never sacrifice quality with these diamonds.


Now that you know how are lab-grown diamonds made, you can see why synthetic diamonds possess the same characteristics as their natural counterparts. While they don’t come from the earth, perceptions are changing, and manmade gemstones have gone mainstream.

Whether you value more sustainable jewelry, support green issues, or want to spend less on a piece of fine jewelry, lab-grown diamonds are the answer.

At Gema & Co., we specialize in selling exquisite lab-grown diamonds that meet the high standards of the four C’s. If you want an authentic piece of beauty on your finger or around your neck, browse our lab diamond and moissanite engagement rings now.
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