In Neal Stephenson’s science fiction masterpiece The Diamond Age: Or, A Young Lady's Illustrated Primer, microscopic nanobots build fantastic structures and extravagant objects out of diamond. They assemble mile-high buildings atom by atom, constructing colossal translucent towers stronger and more durable than anything we can imagine today. Of course those opulent towers are only accessible to a select few elites and the rest of humanity lives in nightmarish toxic squalor, but the theoretical technology is still fascinating. And its based on the very real and very strange properties of diamonds.

Diamonds are made of carbon, the fourth most abundant element in the universe, and the second most abundant element in your body. It is the key element of life, the backbone of organic chemistry. Carbon is special because it so easily bonds with other elements to create a huge variety of compounds and materials, everything from simple sugars to bones. Of course most recently it has gained fame as the core component of carbon fiber, a super-light and super-strong material made from carbon threads and resin. Carbon fiber’s strength is due in large part to its unique arrangements of carbon atoms. Carbon can bond to itself in many ways, creating complex structures with many different properties. In carbon fiber, the element bonds together to create extremely tough chains that resist stretching. Arrange those atoms differently, however, and you get bizarre and astonishing results. 

Diamond is pure carbon arranged in a cubic crystal structure. Each atom is bonded to four other atoms to form a tetrahedron, or pyramid, shape. Carbon in this arrangement is incredibly hard, in fact it’s by far the hardest material we’ve discovered. Hardness is, simply put, how much a material resists denting or scratching. This is a well-known fact; we’ve all seen cat burglars using diamond glass cutters to steal priceless artifacts, or used diamond-coated drill bits or saw blades to cut through tough materials like steel. But diamonds have other amazing properties that are often overlooked.

Diamond has the highest thermal conductivity of any material. That means it can transfer heat better than anything else, which is why real diamonds can feel warm to the touch whereas cheap knockoffs feel cool. To understand just how amazing diamond is at transferring heat, we first need to understand thermal conductivity. Thermal conductivity is measured in Watts per meter-Kelvin, W/mK. A material with a conductivity value of 1 W/mK will transfer heat at a rate of 1 watt for every degree of temperature difference between opposite faces. 

That’s all pretty meaningless without a solid example, though. Pure copper, the famously good electrical and thermal conductor, has a conductivity of around 400 W/mK. Gold measures in at 327 W/mK. Diamond, however, has a thermal conductivity between 1,500-2,200 W/mK.

Why can diamond conduct heat so well? Again, the secret lies in its structure. Heat can quickly and easily propagate through its cubic crystal structure in the form of atomic vibrations called phonons. In condensed-matter physics, a phonon is a unit of vibrational energy that arises from oscillating atoms within a crystal. Heat energy zips right through diamond’s crystal lattice. 

Electrons, however, can’t travel through diamonds at all. This makes them electrically non conductive, in other words an insulator. Combine high thermal conductivity with zero electrical conductivity and you get a material that’s perfect for dissipating heat away from sensitive electronics. Electrical engineers use diamond to quickly and efficiently channel heat away from sensitive circuitry. These components, called diamond heat spreaders, are used in satellites, airplanes, and other equipment that must endure extreme conditions. They’re also used in high-performance computing, LED lighting systems, electric vehicles, radiofrequency (RF) transmitters, and high-power lasers.  

These diamond heat spreaders aren’t made of naturally occurring diamonds, they’re made in a lab. Powerful microwaves blast methane gas, releasing carbon atoms that crystalize around a seed layer of diamond. A diamond wafer grows slowly over time and can then be cut using lasers or other cutting tools with diamond surfaces. Diamond heat spreaders are usually just a few millimeters thick and are placed placed between heat-generating electronic components and larger passive radiators made from other materials like Silicon carbide, copper, or aluminum. Heat passes quickly through the diamond, then into the larger radiator to dissipate further.

Diamond’s other amazing properties make it perfect for extreme conditions. It’s essentially immune to corrosion and resists a wide variety of acids and other chemicals. It can also withstand incredible temperatures.

All of these properties make diamond a dream material for electrical engineers. When mixed or “doped” with other elements like boron, diamond becomes a super semiconductor. Unlike silicon semiconductors, it can withstand tremendous heat and high-frequency, high-power electricity. This makes for more efficient, smaller high-power electronics in power grids, EVs, and more. But unfortunately diamond semiconductors are extremely expensive and difficult to make. Ookuma Diamond Device in Japan, however, has been working on diamond-based semiconductors for decades and is making devices for measuring radioactivity in hazardous environments. The company’s first production facility, and the world’s first dedicated manufacturing base for diamond semiconductors, is planned for Fukushima Prefecture. The organization is also working with Hokkaido University, the National Institute of Advanced Industrial Science and Technology (AIST), the National Institute of Technology, and Fukushima College to develop diamond microprocessors and memory devices. They expect these devices to be used in nuclear decommissioning and space applications.

Diamond definitely has amazing physical properties, but it remains an exotic material despite recent advances in manufacturing techniques. The world of diamond skyscrapers described in Stephensen’s Diamond Age is still far from reality. Hopefully one day engineers will develop an efficient, effective molecular manufacturing or crystallographic technique that can be used to make diamonds in any shape, but for now we’re stuck with slow, energy intensive, persnickety methods. Still, without those methods, scientists wouldn’t have access to amazing equipment like the James Webb space telescope and more.