Consumers looking for alternatives to mined diamonds will discover a wealth of options to choose from, from simulants like cubic zirconia and moissanite to lab-grown diamonds. While cubic zirconia and moissanite are stones that look like diamonds but have different chemical compositions, lab-grown diamonds are chemically identical to mined diamonds, making them the superior choice. The difference is that it takes nature millions of years to make a diamond, but we can grow one in a matter of weeks.

All lab-grown diamonds are grown using either the High Pressure, High Temperature (HPHT) method or the Chemical Vapor Deposition (CVD) method. Both methods start with a diamond seed, taken either from a mined or a lab-grown specimen. And both methods are capable of producing clear, colorless diamonds of the highest quality.

As knowledge of the natural world advanced through the 18th and 19th centuries, scientists began to draw a clearer picture of the way minerals form underground. Some gemstones, for example, are formed when mineral-rich water deposits minerals into cavities in the Earth’s surface. Those minerals are layered and compressed over millions of years, forming gemstones like opal. Others are formed when intense heat and pressure melts rock, which then cools and hardens into a new shape: a crystal matrix. Diamonds are formed when this heat and pressure rearranges pure carbon from its typical flat 2D shape to a 3D crystal.

Once scientists understood more about this process, they began trying to replicate it in a laboratory setting. (Read more about this fascinating history here [link: https://primolabgrown.com/blog-menu/12-lab-grown-diamonds-a-century-of-growth]). The results of these experiments are the two main methods for growing diamonds used today: HPHT and CVD.

High Pressure, High Temperature (HPHT)

The High Pressure, High Temperature method was the first to produce gemstone-quality diamonds. This process mimics the way diamonds form in nature. A diamond seed, surrounded by carbon, is placed in a press and subjected to extreme heat and pressure—1300-1600°C and 870,000 psi, the same heat and pressure at which diamonds form in the upper mantle. The carbon melts in a molten solution of nickel and iron, and as it cools, the carbon atoms crystalize around the diamond seed, adding layers of pure carbon to the diamond, effectively growing a diamond around the original seed.

Just like mined diamonds, HPHT diamonds often contain minute traces of nitrogen or boron. Nitrogen can give a diamond a yellow tint, while boron can be added to create blue diamonds. But that isn’t to say that diamonds grown using the HPHT method are only yellow or blue. The HPHT method can produce the full range of diamond colors, including colorless diamonds.

Chemical Vapor Deposition (CVD)

The CVD method is a more recent development that follows roughly the same principle of growing a diamond by adding layers of carbon to an existing diamond seed. The difference is that the CVD method requires much lower temperatures and pressures by using microwaves and vapor. It works like this: the diamond seed is placed into a vacuum chamber, and the chamber is then filled with hydrocarbon gas. The gas is heated and bombarded with a microwave beam, which separates the hydrogen from the carbon. The carbon then bonds with the diamond seed, growing a diamond one carbon atom at a time.

It is often said that CVD method produces type IIA diamonds, which are colorless, extremely pure, and extremely rare in nature, containing almost no nitrogen or boron. This isn’t exactly true; while CVD diamonds are chemically pure, the diamond that comes out of the chamber is often brown in color. These brown diamonds are then decolorized by post-growth HPHT treatment.

It was once quite difficult to produce a colorless diamond using the HPHT method, but technological advancements and the refinement of techniques has made it much easier. We only sell the highest quality diamonds we produce, and all of our diamonds are sold as-grown, with no post-growth HPHT color treatment.

Primo Diamonds, the premier supplier of lab-grown diamonds, has released a new diamond offering for American Gem Society members. This new diamond line, Primo Select, is only available only through AGS Member Stores. The Primo team has over 100 years of collective experience in the diamond trade and are experts in both mined and lab-grown diamonds. With Primo Select, AGS members can be sure that they are getting only the highest-quality lab-grown diamonds.

As lab-grown diamonds become more and more affordable, we will see more of a distinction between lab-grown diamonds used in fashion jewelry and lab-grown diamonds used in luxury jewelry. Luxury lab-grown diamond consumers are interested in the novelty of the technology, the perception of sustainability, and the ability to acquire a much bigger diamond than they thought possible. But not all lab-grown diamonds are the same. There are differences in quality, as different growing methods will result in diamonds of varying color and clarity, and uncontrollable variables can also affect the final product.

While we do have a great deal of control over the diamond growing process, growing diamonds in a lab is as much art form as exact science, as the HPHT method we use mimics the way diamonds grow deep inside the Earth. As a result, not all of the diamonds we grow make it to market. We maintain high standards of quality and offer our customers only the best as-grown material. The diamonds we offer through the Primo Select program are chosen from the top 1% of the gemstone-quality rough diamonds that we produce.

But selecting only the best roughs is only the first step to producing a superior diamond. The beauty of a diamond is dependent on both the quality of the rough and the quality of the cut. It takes an expert eye to spot a high-quality rough and properly evaluate its potential.

But no matter how big, clear, and colorless your rough diamond is, it still takes a master gemcutter to bring out the diamond’s fire, sparkle, and brilliance—those qualities that make diamonds so alluring. Cut is the most important of the 4Cs, and an inferior piece of rough diamond with a superior cut will often look more beautiful than a superior piece of diamond rough with an inferior cut. That’s why we say “The Beauty is in the Cut.” A perfect lab-grown diamond still needs the perfect cut to shine. We combine the top 1% of our diamond selection with a masterful cut, integrating new technology with old-world craftsmanship. The result is Primo Select.

Last year, InStore Magazine asked hundreds of jewelry retailers for their thoughts on the next big jewelry trend, and they all said the same thing: lab-grown diamonds are set to take over the industry. The technology for growing diamonds by subjecting a diamond seed to heat and pressure has existed for decades, but gemstone-quality lab-grown diamonds only became a viable commodity in the 2010s. In the past decade, their popularity has surged, and without any concerted marketing effort by the lab-grown diamond industry, over half of consumers are now aware of lab-grown diamonds, up from 9% in 2010. So how do we explain this explosion in interest in lab-grown diamonds?

Three factors are driving the growth of lab-grown diamonds: affordability, sustainability, and awareness. The cost of lab-grown diamonds has decreased, particularly at smaller carat weights, but larger, higher-quality lab-grown diamonds still fetch higher prices, albeit some 60% lower than their mined equivalents. At the top end of the market, luxury consumers are drawn to the possibility of larger stones of extremely high quality incorporated into more complex, creative designs.

The biggest area of growth for lab-grown diamonds has been in the bridal category. Consumer attitudes still closely associate diamonds with engagement rings. Lab-grown diamonds make diamonds accessible to those who could never afford a diamond to begin with, and it lets those who can afford a diamond purchase an even larger diamond. Again, it is younger consumers leading the charge, with nearly 70% of Americans between the ages of 21 and 40 and 66% of Millennials reporting that they would consider a lab-grown diamond for their engagement ring, while 23% say they will definitely buy a lab-grown diamond engagement ring.

The second factor making lab-grown diamonds more attractive is the negative press the mining industry has suffered in recent years. For many consumers, their distaste for everything from conflict diamonds to the environmental destruction caused by mining is stronger than the appeal of the gemstone. This is true especially for Millennial consumers, who now account for 60% of all diamond buyers in the US despite making up only 20% of the population. Gen Z are even more invested in ethical consumption than Millennials, so it is likely that even with reforms to the mining industry, future consumers of diamonds will continue to opt for the lab-grown alternative, seeing it as an ethical, sustainable alternative.

Finally, growing awareness of the fact that lab-grown diamonds are not diamond simulants has spurred consumer acceptance. The 2018 Federal Trade Commission ruling defining a diamond as “a mineral consisting essentially of pure carbon crystallized in the isometric system” certainly helped in this regard. It doesn’t matter if the carbon was crystallized over millions of years underground or over a few weeks in a machine, the result is the same: a crystal of nearly pure carbon.

As a new generation of fine jewelry consumers realigns the market to their values, producers, wholesalers, and retailers of lab-grown diamonds stand to benefit. Some retailers, even ones as big as Pandora, are already shifting to a lab-grown-only model in response to growing consumer demand for sustainable products. It seems the general public is discovering what we’ve known for years: lab-grown diamonds are the future.

The introduction of lab-grown diamonds to the diamond market may leave some consumers confused as to what they are actually getting when they purchase a lab-grown diamond. This is especially true as lab-grown diamonds become more and more affordable. In addition to being marketed under different names such as “synthetic” or “cultured” diamond, lab-grown diamonds may be confused with diamond simulants such as cubic zirconia. But the two are not the same. The difference is that lab-grown diamonds are chemically identical to mined diamonds, while cubic zirconia is a different substance entirely. Let’s get into exactly what that means.

A diamond, as you probably know already, is a mineral composed of about 99.95% carbon. Graphite and, to a lesser extent, coal are also mostly composed of carbon, but the difference is that in a diamond, intense heat and pressure have crystallized the carbon atoms into a three-dimensional lattice structure. Various other elements may comprise the other 0.05% of a diamond, and it's those trace elements that determine the color of a diamond: when nitrogen replaces carbon in parts of the crystal, you get a yellow diamond and the presence of boron leads to a blue diamond.

The process by which a flat chain of carbon atoms is restructured into a cubic crystal requires a great deal of heat and pressure. The heat and pressure required—1300°C (2400°F) and pressure 240,000 times the pressure found at sea level—occurs in the upper mantle, 150 km (90 miles) deep.

What are Lab-Grown Diamonds?

Throughout the 18th, 19th, and 20th centuries, scientists gained a more thorough understanding of the chemical composition of minerals and the geological processes that created them. In the 19th century, scientists like Henri Moissan hypothesized that the sort of heat and pressure required could be reproduced in a laboratory. Using the new electric technology of the day, he claimed to have grown diamonds.

Early attempts at growing diamonds resulted in stones too small and too brown to be of any value—if what was being created were diamonds at all and not a substance like silicon carbide. It wasn’t until the invention of the belt press that the dream of growing diamonds that were both useful to industry and gemstone-quality became a reality.

The belt press, invented by General Electric engineer Tracy Hall in 1954, produced temperatures of over 1600°C and 1.5 million pounds per square inch of pressure. This temperature was much lower than the 3500°C of Moissan’s electric arc furnace, but the pressure was far more than anyone in the late 1800s could have imagined possible.

The technique GE used to grow diamonds, called High Pressure, High Temperature (HPHT), did not produce diamonds large and clear enough to be used as gemstones until the 1970s. Around the same time, the Chemical Vapor Deposition (CVD) method began producing gemstone-quality diamonds. CVD grows diamonds at lower temperatures and pressures than HPHT by sealing a diamond seed in a chamber full of hydrocarbon gas. The chamber is then heated by microwaves, which breaks the hydrocarbon gas down into hydrogen and carbon. The carbon then bonds with the diamond seed, building a diamond crystal atom by atom.

Why “Lab-Grown”?

The result of both the HPHT and CVD methods is a crystalline mineral of almost pure carbon. A mineral composed of 99.95% or more carbon is a diamond, whether it was grown in molten rock under extreme heat and pressure in the upper mantle, in a gas-filled chamber heated by microwaves, or in the pressure of a mechanical press. For this reason, diamonds produced this way are referred to as “lab-grown” rather than synthetic. The term “synthetic” denotes a material produced by synthesis (combining two or more different substances) in order to imitate another substance. Lab-grown diamonds don’t imitate diamonds; they are diamonds. And since the methods produce actual diamonds, they are not “imitation” diamonds or “diamond simulants.” “Lab-grown diamond” is the most accurate way to describe the product of these processes.

What is Cubic Zirconia?

While lab-grown diamonds are chemically identical to diamonds, cubic zirconia (CZ) is a different substance altogether. Its brightness and clarity, not to mention its affordability, make it a great diamond simulant. But it is susceptible to dulling over time due to the accumulation of dirt. Nevertheless, it is almost indistinguishable from diamond to the untrained eye. But overall it is a far less durable stone. While diamond (both the mined and lab-grown kinds) rates a 10 on the Mohs hardness scale, the hardness of CZ is only 8. Nothing will scratch or chip a diamond, but CZ is likely to scratch, chip, and turn cloudy over years of daily use. This is because CZ is not a diamond but zirconium dioxide (ZrO2). It occurs rarely in nature; the cubic zirconia used in jewelry is synthesized by combining zirconium oxide powder with magnesium or calcium at 2750°C (4,982°F).

Whether your reasons for seeking an alternative to mined diamonds are about affordability or ethics, both cubic zirconia and lab-grown diamonds are both great alternatives. But only lab-grown diamonds are actual diamonds, with the same hardness, clarity, color, and unmistakable sparkle you expect from a diamond.