In nature, it takes billions of years to form a diamond. Most of the diamonds nature produces are too impure for jewelry or high-tech industry, and extracting them is costly and dirty. In the lab, diamonds can be made faster, purer, and cheaper, overcoming these problems and making possible new uses for diamonds that were previously unattainable.
Scientists first manufactured diamonds in laboratories in the 1950s, imitating the conditions under which diamonds were produced in nature. The diamonds produced were initially small and impure and so useful only in low-tech industrial products such as abrasives and lubricants. Since then, diamond manufacturing technology has progressed: the generation process has become more controlled, new methods have been invented, and better catalysts have been discovered. Diamonds grown in the lab are now cheaper than mined diamonds and have superior physical, optical, chemical, and electrical properties. Consequently, they dominate the industrial market. In the past decade, diamond manufacturing technology progressed so much that it is now possible to mass-produce jewelry-quality diamonds in the lab. These lab diamonds are cheaper and more beautiful than mined diamonds. A perfectly cut, flawless lab diamond costs a fraction of the price of a mined diamond of lesser quality. (...)
The Future of Jewelry
The tradition that diamonds are an integral part of an engagement proposal is the result of a highly successful advertising campaign by the De Beers cartel. During the Great Depression, diamond sales slumped. De Beers responded by enlisting Hollywood actors and socialites in a campaign to associate diamond rings with marriage proposals, commissioning portraits of them showing off their new engagement rings, and by running ads showing happy young couples honeymooning above the now-famous slogan ‘A Diamond Is Forever’. In time, it also tried to persuade men that they would need to spend a fixed proportion of their income on a stone to win at love. One later advert, from the 1980s, was captioned ‘2 months’ salary showed the future Mrs Smith what the future would be like’.
Lab diamonds have destroyed this equilibrium. Competition among diamond manufacturers and technological progress in diamond making mean that lab diamonds are indistinguishable from mined diamonds, but cost much, much less – and the price is falling. In 2016, a one-carat near-colorless and very slightly included round brilliant lab-grown diamond cost $5,440, according to diamond analyst Paul Zimnisky; in 2024, the same stone cost $1,325. (The price of an equivalent mined diamond decreased from $6,538 to $5,035.) In the past few years, sales of lab diamonds have started to overtake mined diamonds. A survey by The Knot of nearly 10,000 couples married in 2023 revealed that lab diamonds accounted for 46 percent of engagement rings (compared with 39 percent who opted for a mined diamond), up from 12 percent in 2019.
Diamonds will continue to symbolize engagement – the tradition is now well established – but on its own, the raw material will cease to be a symbol of wealth or sacrifice. Lab diamonds can already be made to be clearer and more colorless than mined diamonds – or, if the wearer desires it, to have a more magnificent color. To complement this, consumers are demanding better workmanship in the cutting and polishing of the stone and in the design and manufacturing of its setting.
The ‘hearts and arrows’ optical pattern, which is present only in round brilliant diamonds that are perfectly cut, is a good example of this trend. Previously, perfectly cut diamonds were extremely rare, and too expensive for most customers. Now, because of strong demand, the International Gemological Institute has begun to note the presence of the hearts and arrows pattern on their diamond grading certificates.
As lab diamonds can be engineered to be more beautiful than mined diamonds, we should expect them to be used more often in fine jewelry. Lab diamonds won’t end conspicuous consumption, but it will be the consumer and not the mine owners who enjoy most of the benefits. (...)
Diamonds in Industry (...)
As an optical material, diamonds have tremendous potential, because they are transparent, dissipate heat quickly, and do not expand much at high temperatures. In particular, diamonds are useful in high-powered lasers, which are used in cutting, welding, sensing, ignition, and medical surgery. A major problem with existing high-powered lasers is that their components are damaged by or deteriorate under high heat, limiting their output. An example of this is the thermal lensing effect, where high and uneven temperatures change how the optical window of the laser bends light. This degrades the focus and alignment of the laser beam. Diamond, however, is an excellent window material, being a good conductor of heat and transmitter of light and having a refractive index that does not vary much with temperature. Diamonds can also be used as heat spreaders to cool down other components in lasers, increasing the maximum power that can be generated.
An ongoing area of research is the use of diamonds as the active laser medium: the component that optically amplifies light. To do this will require diamonds that are larger, purer, and more structurally perfect than what nature can provide and so will depend on advances in diamond-manufacturing technology.
Even more promising, diamond has the potential to be an excellent semiconductor. Diamond has excellent thermal conductivity, because the regularity of its lattice and the strength of its bonds enable heat to be transferred quickly and efficiently. It has a wide band gap – in other words, it requires a high (but not insurmountable) amount of energy to promote one of its electrons into the conduction band. This means diamond can handle higher temperatures and voltages than conventional semiconductors, making it useful not only in devices that operate in extreme conditions (such as engines, radio towers, drilling equipment, spacecrafts, solar panels, and the electricity grid) but also for increasing microchip performance more generally.
Most microchips today are made from silicon, a metalloid that sits one row below carbon on the periodic table and has a thermal conductivity of 1.5 watts per centimeter-kelvin. Diamond, by contrast, has a thermal conductivity of 22 watts per centimeter-kelvin. Over the past five decades, the number of transistors on a microchip has increased at an exponential rate, while the microchips themselves have become smaller. Chip designers have therefore had to contend with the ever-increasing problem of dissipating the heat that is generated. Heat degrades the performance of microchips and limits how tightly transistors can be packed together.
To overcome this problem, manufacturers have lowered the voltage and devoted a large amount of space and energy to cooling and ventilating systems. Because diamond dissipates heat much faster than silicon, diamond-based microchips can be made smaller and operate in more extreme temperatures. On existing silicon-based microchips, diamonds are already being used as heat spreaders.
Diamond also has a wider band gap than silicon (5.45 electron volts vs. 1.1 electron volts) and consequently diamond microchips can operate at higher voltages than silicon microchips. Semiconductors are engineered to precisely control the flow of electricity, but above a certain voltage their electrical resistance breaks down, resulting in an uncontrolled flow of current. Diamond undergoes electrical breakdown at ten millivolts per centimeter, compared to 0.3 for silicon, making it more suitable for high-voltage applications such as power generation and distribution. Furthermore, for a given voltage, less material is needed and so diamond microchips can be made to be smaller.
by Javid Lakha, Works in Progress | Read more:
As an optical material, diamonds have tremendous potential, because they are transparent, dissipate heat quickly, and do not expand much at high temperatures. In particular, diamonds are useful in high-powered lasers, which are used in cutting, welding, sensing, ignition, and medical surgery. A major problem with existing high-powered lasers is that their components are damaged by or deteriorate under high heat, limiting their output. An example of this is the thermal lensing effect, where high and uneven temperatures change how the optical window of the laser bends light. This degrades the focus and alignment of the laser beam. Diamond, however, is an excellent window material, being a good conductor of heat and transmitter of light and having a refractive index that does not vary much with temperature. Diamonds can also be used as heat spreaders to cool down other components in lasers, increasing the maximum power that can be generated.
An ongoing area of research is the use of diamonds as the active laser medium: the component that optically amplifies light. To do this will require diamonds that are larger, purer, and more structurally perfect than what nature can provide and so will depend on advances in diamond-manufacturing technology.
Even more promising, diamond has the potential to be an excellent semiconductor. Diamond has excellent thermal conductivity, because the regularity of its lattice and the strength of its bonds enable heat to be transferred quickly and efficiently. It has a wide band gap – in other words, it requires a high (but not insurmountable) amount of energy to promote one of its electrons into the conduction band. This means diamond can handle higher temperatures and voltages than conventional semiconductors, making it useful not only in devices that operate in extreme conditions (such as engines, radio towers, drilling equipment, spacecrafts, solar panels, and the electricity grid) but also for increasing microchip performance more generally.
Most microchips today are made from silicon, a metalloid that sits one row below carbon on the periodic table and has a thermal conductivity of 1.5 watts per centimeter-kelvin. Diamond, by contrast, has a thermal conductivity of 22 watts per centimeter-kelvin. Over the past five decades, the number of transistors on a microchip has increased at an exponential rate, while the microchips themselves have become smaller. Chip designers have therefore had to contend with the ever-increasing problem of dissipating the heat that is generated. Heat degrades the performance of microchips and limits how tightly transistors can be packed together.
To overcome this problem, manufacturers have lowered the voltage and devoted a large amount of space and energy to cooling and ventilating systems. Because diamond dissipates heat much faster than silicon, diamond-based microchips can be made smaller and operate in more extreme temperatures. On existing silicon-based microchips, diamonds are already being used as heat spreaders.
Diamond also has a wider band gap than silicon (5.45 electron volts vs. 1.1 electron volts) and consequently diamond microchips can operate at higher voltages than silicon microchips. Semiconductors are engineered to precisely control the flow of electricity, but above a certain voltage their electrical resistance breaks down, resulting in an uncontrolled flow of current. Diamond undergoes electrical breakdown at ten millivolts per centimeter, compared to 0.3 for silicon, making it more suitable for high-voltage applications such as power generation and distribution. Furthermore, for a given voltage, less material is needed and so diamond microchips can be made to be smaller.
by Javid Lakha, Works in Progress | Read more:
Image: French chemist Henri Moissan attempting to synthesize diamonds by quenching hot carbon in water. Credit: Alarmy
