Synthetic Diamonds

Podcast Transcript

For thousands of years, diamonds have been among the most valuable substances on Earth.

Diamonds are not only the hardest substances known, but they are also incredibly hard to find.

However, in the last several decades, researchers have discovered ways to make diamonds in the lab, and they are now being made at scale.

It has the potential to revolutionize multiple industries.

Learn more about synthetic diamonds and how they are changing the use and value of diamonds on this episode of Everything Everywhere Daily.

In a previous episode, quite a while ago, I covered diamonds. That was more of a high-level overview, and in it, I mentioned the creation of synthetic diamonds.

In this episode, I want to go deeper into one of the biggest topics in materials science.

First, a brief recap of what makes diamonds special.

Diamonds are made out of carbon. That’s it. There are different ways you can arrange pure carbon atoms in what is known as an allatrope. The most common is graphite, in which carbon atoms are arranged in a two-dimensional sheet.

Diamonds are a three-dimensional lattice of carbon atoms. Getting them to form this three-dimensional lattice is extremely difficult and can only be done at extremely high temperatures and pressure. In nature, this can only be done deep inside the Earth.

The diamonds most people have encountered throughout history reached the surface after being transported from deep within the Earth. This is extremely rare, meaning there are only a few places on the planet where natural diamonds can be found.

Diamonds have several exceptional properties. As most of you probably know, diamonds are the hardest natural substance known. That isn’t their only notable feature, however.

Diamond has the highest thermal conductivity of any bulk material at room temperature. Meaning, if you want to transport heat away from something, you can’t beat diamond. It also means that diamond is a horrible thermal insulator.

Diamond is optically transparent across a wide range of electromagnetic wavelengths as well.

The problem is that diamonds are also very pretty, when cut correctly, and can fetch a very high price.

The high price of diamonds, coupled with their extreme usefulness in industrial and commercial applications, posed a problem.

That then raised the question: if the conditions deep inside the Earth can be replicated in a laboratory, can we create diamonds?

The quest to create diamonds artificially dates back centuries, with early alchemists and scientists attempting various methods to transform carbon into its most prized crystalline form. However, it wasn’t until the mid-20th century that legitimate success was achieved.

In 1954, scientists at General Electric, led by Tracy Hall, successfully created the first reproducible synthetic diamonds using a high-pressure, high-temperature process. This breakthrough came after years of failed attempts and represented a watershed moment in materials science.

Hall’s team used a belt press apparatus that could generate the extreme conditions necessary for diamond formation, pressures exceeding 1.5 million pounds per square inch and temperatures around 1,500 degrees Celsius.

The first synthetic diamonds were small and primarily suitable for industrial applications rather than jewelry. Throughout the 1960s and 1970s, the technology improved, with companies like De Beers also developing their own methods, though they initially focused on industrial rather than gem-quality production.

The landscape shifted dramatically in the 1980s and 1990s with the development of Chemical Vapor Deposition, or CVD, technology. This alternative method opened new possibilities for creating larger, higher-quality diamonds.

Today, there are two dominant growth routes, and most of the modern market is some mix of them.

HPHT, or high-pressure, high-temperature, is essentially a fast, engineered version of deep-Earth conditions. Carbon source material, which is often graphite and a small diamond “seed” crystal, is placed in a press with a metal solvent-catalyst.

Under very high pressure and high temperature, the carbon dissolves into the molten metal and then precipitates onto the seed, building a larger diamond crystal.

CVD grows diamond from a carbon-bearing gas rather than dissolving carbon in a molten metal. A diamond seed sits in a vacuum chamber while a hydrogen-rich gas mixture with a carbon source, usually methane, is energized, often by microwave plasma.

Carbon deposits on the seed and crystallize as diamond, layer by layer. Over time, the rough crystal is cut off, and the surface can be re-prepared for further growth.

From the 1980s through the 1990s, both HPHT and CVD technologies advanced steadily. Improvements in press design, catalysts, and temperature control allowed HPHT diamonds to grow larger and purer. At the same time, CVD technology benefited from advances in plasma physics, vacuum systems, and semiconductor manufacturing.

Researchers learned how to suppress graphite formation, control crystal orientation, and reduce defects. During this period, synthetic diamonds began to appear that were optically transparent and of gem quality, although production volumes remained small and costs high.

The late 1990s and early 2000s marked a turning point. Companies in Russia, Japan, China, and later the United States and Europe expanded industrial diamond production dramatically.

China, in particular, became a dominant producer of synthetic diamonds for industrial uses. Meanwhile, gemological laboratories such as the Gemological Institute of America developed reliable methods to distinguish natural diamonds from synthetic ones, which became increasingly important as lab-grown stones entered the jewelry supply chain.

In the early 2000s, small numbers of lab-grown diamonds began appearing in the consumer market.

Here I need to reiterate, just in case it hasn’t been clear, that synthetic diamonds are chemically exactly the same as natural diamonds.

Jewelers and gemologists distinguish natural diamonds from synthetic ones by examining subtle growth features and trace signatures that reflect how the crystal formed, rather than by basic appearance.

Using specialized instruments, laboratories look for internal patterns such as growth zoning, metallic inclusions from HPHT catalysts, or layered growth structures typical of CVD diamonds, which differ from the irregular, geological growth features seen in natural stones.

For decades, lab-grown diamonds were confined to industrial uses, which actually strengthened the mined diamond industry by preserving natural stones almost exclusively for jewelry.

However, once gem-quality synthetic diamonds became commercially viable in the late 1990s and especially the 2010s, the boundary between industrial material and luxury product collapsed.

Consumers were suddenly presented with stones that were chemically and physically identical to mined diamonds but available in larger sizes, higher clarity, and lower prices.

This introduced real price competition into a market that had historically avoided it. Lab grown diamonds behave economically like manufactured goods rather than mined commodities. As production capacity expanded, costs fell rapidly.

Retail prices for lab-grown diamonds declined year after year, often dramatically, while natural diamond prices stagnated or declined modestly. The widening price gap forced retailers to confront uncomfortable questions from consumers about value, markup, and long-term worth.

Synthetic diamonds also disrupted the resale and investment narrative around natural diamonds. While diamonds were never truly liquid investments, the perception that they held long-term value was important to consumer psychology.

The existence of a visually identical product with rapidly falling prices highlighted that much of a diamond’s value was social rather than intrinsic. This realization has been particularly damaging to the mid-market segment, where buyers are more price sensitive and less motivated by extreme rarity.

In response, the traditional diamond industry has increasingly repositioned natural diamonds as luxury goods defined by origin, geology, and story rather than by material properties alone.

Marketing shifted toward emphasizing natural formation over billions of years, uniqueness, and emotional authenticity. Certification schemes expanded to include provenance, and narratives around craftsmanship, heritage, and romance were reinforced.

In effect, natural diamonds began to resemble fine art or wine more than industrial materials, with value tied to narrative and scarcity rather than function.

Yet, most of this was marketing, as they are still chemically the same as synthetic diamonds.

The production of synthetic diamonds has experienced explosive growth over the past two decades. In the early 2000s, global production of gem-quality synthetic diamonds was negligible, measured in thousands of carats annually.

By 2020, production had reached several million carats per year, and estimates for 2023 suggest production may have exceeded ten million carats. This represents more than a thousandfold increase in just two decades. The growth has been driven by technological improvements, increased investment, and expanding production facilities, particularly in China, India, and the United States.

The price trajectory of synthetic diamonds tells an amazing story. In the mid-2000s, gem-quality lab-grown diamonds commanded prices only marginally below natural diamonds, sometimes reaching 80 to 90 percent of comparable natural stone prices.

However, as production scaled and technology matured, prices began falling precipitously. By 2015, lab-grown diamonds typically sold for about 30 to 40 percent less than natural diamonds. This discount widened dramatically in subsequent years.

By 2020, one-carat lab-grown diamonds were selling at roughly 40-50 percent off natural diamonds. By 2023, the differential had grown even larger, with many lab-grown diamonds priced at 70 to 90 percent below comparable natural diamonds.

A one-carat natural diamond that might cost $4,000 to $6,000 could have a lab-grown equivalent available for $400 to $800 or even less from some producers.

While gem-quality diamonds get most of the attention, this really isn’t the most interesting aspect of synthetic diamonds. It is for industrial uses.

The impetus for this episode came from my research into speakers for a hi-fi sound system. Many speakers claim to have diamond-coated tweeters.

This struck me as odd, so I began to dig into why this is even a thing.

Diamond-coated tweeters are used because diamond is exceptionally stiff, very light for its strength, and does not flex easily, which helps a speaker reproduce high frequencies more cleanly and accurately.

The stiffer the tweeter dome is, the less it bends as it moves, reducing distortion and making details sound clearer. To make them, manufacturers form a very thin dome from a lightweight metal and then coat it with a microscopic layer of diamond.

Speakers are just the tip of the iceberg.

The largest industrial use of diamonds is in cutting, grinding, drilling, and polishing. Diamond abrasives are bonded into saw blades, drill bits, grinding wheels, and polishing pastes used for cutting stone, concrete, asphalt, ceramics, glass, and hardened metals.

In manufacturing, diamond tools are essential for machining precision components, including engine parts, turbine blades, and semiconductor wafers.

Oil and gas drilling relies on diamond impregnated drill bits that can survive intense heat, pressure, and abrasion deep underground. In electronics manufacturing, diamond abrasives are used to slice silicon and other crystals into wafers with extremely tight tolerances.

Another major industrial role is heat management. This makes it extremely valuable as a heat spreader or heat sink in high-power electronics, such as radio frequency amplifiers, laser diodes, and power transistors.

Synthetic diamond plates are already used in niche applications where overheating limits performance or reliability. As prices fall, diamond heat sinks become viable in more mainstream electronics.

As diamonds get cheaper and production techniques improve, you can expect to see diamonds in more and more applications. If you have ever used a heat sink on a computer CPU, the ultimate heat sink would be one made of diamond.

One of the biggest things that synthetic diamond manufacturers are working on today is adding impurities to diamonds.

A perfectly pure diamond is often less useful than a diamond with carefully controlled defects. By introducing elements such as nitrogen, boron, or silicon during growth, manufacturers can tune the diamond’s color, electrical behavior, optical properties, and quantum characteristics.

In jewelry, nitrogen or boron can create yellow, blue, or other fancy colors on demand, increasing product variety and value. In electronics, boron doping can make diamond electrically conductive, opening the door to high-power semiconductors that outperform silicon in extreme environments.

In sensing and quantum technologies, specific defects, such as nitrogen-vacancy centers, enable diamond to detect magnetic fields, temperature, and strain with extraordinary precision.

Rather than flaws, these impurities make diamond a customizable engineering material, and as synthetic production improves, controlling defects has become one of the most critical ways to expand diamond’s practical and commercial uses.

Despite the enormous impact synthetic diamonds have had in the jewelry industry, we are only just beginning the widespread use of diamonds in everyday applications.

As production techniques improve and costs decrease, we will see diamonds in more and more products, which will perhaps usher in a new diamond age.