Diamonds Aren’t Just for Jewelry

Diamonds first became valuable over 2000 years ago (discovered over 4000 years ago) in India. Due to their hardness, rarity, and ability to reflect light, they were prized possessions of the wealthy. While the tradition of diamond engagement rings started in 1477 with Archduke Maximilian of Austria, not until more recently did they become a universally recognized symbol for romance when the De Beers company launched the “Diamonds are Forever” campaign (1947).

While most of us recognize diamonds for jewelry, nearly all diamonds produced on Earth never touch jewelry. The world manufactures more than 14.6 billion carats of diamond every year for industrial use, while natural diamond mining, the source of most gems, is forecast to fall to just 120 million carats by 2030. In other words, for every carat that’s mined out of the Earth, we manufacture more than 100 carats in a lab, and virtually all of that lab-grown output goes into industry, not rings. No major natural diamond deposit has been discovered in over 20 years and most mines are past peak production.

This inversion is the result of a massive price collapse. Since 2018, wholesale lab-grown diamond prices have fallen roughly 90% and there is roughly a 75% difference in price per carat between natural and synthetic diamonds. While this was devastating to jewelers, it was a gift for engineers.

Diamonds are an Engineer’s Best Friend

When looking more into the spec sheet of a diamond, you can begin to understand why they are attractive for engineering. Diamond is the strongest and hardest known material and also has the highest thermal conductivity of any material at room temperature (2,200 W/m-K – measures thermal conductivity – compared to roughly 150 for silicon and about 400 for copper). Simply, the material we predominantly use as jewelry is more than 5x better at moving heat than the metal we use to build heat sinks.

When looking at the electrical properties, it's just as extreme. Every semiconductor has what's called a "bandgap," which is the amount of energy needed to knock loose the electrons that carry electrical current through it. A smaller bandgap means electrons are harder to control when things get hot or voltages get high, which is why your laptop throttles itself and power converters need bulky cooling.

Diamonds have a bandgap of 5.5 eV (electron-volt) which is nearly five times that of silicon (1.1eV), and still well beyond silicon carbide (3.26 eV) and gallium nitride (3.4 eV), the materials currently powering the electric vehicle (EV) revolution. In practice, this means that diamond electronics can keep working in conditions that would fry anything else.

Diamond can also withstand enormous voltages before failing (a “breakdown field” over 10 MV/cm, several times better than its closest rival). Diamonds are the “Ultimate Semiconductor”.

Historically, you couldn’t order diamonds to spec, you had to dig them up and take what the Earth gave you. Two growth methods changed this: HPHT (high pressure/high temperature) and CVD (chemical vapor deposition).

• HPHT: take carbon, squeeze it at pressures found hundreds of miles underground, heat it to around 1,500°C, and out comes a diamond in weeks instead of a billion years
• CVD: Inside a vacuum chamber, microwaves tear apart a carbon-rich gas, and the freed carbon atoms settle onto a thin diamond "seed," stacking up layer by layer like 3D printing at the atomic scale

CVD is the most important with respect to engineering and technology because the layer by layer control is what turns diamond from a gem into an engineering material. The “growers” can decide how pure each layer is.

How Are Diamonds Used Today (and Tomorrow)

Today, nearly all industrial diamonds go into saw blades, drill bits, and abrasives (including the tools that slice and polish silicon wafers into computer chips). Thin plates of lab-grown (CVD) diamond can also act as tiny radiators, drawing heat away from high-power electronics like radar amplifiers and laser diodes. Smaller niches like laser windows, surgical scalpels, high-end speakers, and radiation sensors all follow the same theme: wherever a job is too hot, too hard, or too extreme for ordinary materials, diamonds are your best friend.

Tomorrow, this theme will scale up. AI chips today burn past 1,000 watts each (about as much as a space heater) and getting that heat out is becoming the biggest bottleneck in computing. Diamond-cooled servers already run their chips 10-20°C cooler, and researchers today are growing diamond directly onto chips. While this would be a major leap, the next step could be making the chip itself out of diamond which could handle more power while wasting less of it, in smaller devices for EVs, the power grid, or aerospace.

One of the really interesting use cases is leveraging the synthetic diamond process to create NV centers (nitrogen-vacancy). It is essentially a “useful flaw” in the creation of the diamond that traps an electron which is extremely sensitive to magnetic fields, a tiny compass needle. Reading it is extremely easy too: shine a green laser at the diamond and the flaw glows red and how brightly it glows tells you exactly what magnetic field the electron is feeling. This could create sensors precise enough to detect the faint magnetic signals of the human body, to navigate a plane without GPS, or to potentially even serve as the building blocks of quantum computers.

One of the strangest use cases is that diamond electrodes can also be used to snap the near-unbreakable bonds of PFAS “forever chemicals”, breaking them down into carbon dioxide, water, and fluoride.

Takeaway: The diamond industry’s identity crisis, marked by collapsing jewelry prices and shrinking mines, is really a transformation story. As lab-grown diamonds make the material cheaper, purer, and engineerable to precise specifications, diamond’s value is shifting from what it symbolizes to what it can physically do. A material once reserved for rings is becoming a solution to some of technology’s hardest problems, from cooling overheated AI chips and enabling GPS-free navigation to destroying forever chemicals. Within a decade, the most important diamonds will be the ones embedded in your devices, your car, and even your water supply.

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