Diamonds from fossil fuels
To create diamonds, the scientists take a clump of white dust, squeeze it out into a diamond-studded pressure chamber, and shoot it with a laser. When they open the chamber, a new microscopic speck of pure diamond glitters from the depths.
The team's study shows how, with subtle adjustments of heat and pressure, the recipe above produces diamonds from a kind of hydrogen and carbon molecule found in crude oil and natural gas around the world.
"What's exciting about this paper is it shows a way of cheating the thermodynamics of what's typically required for diamond formation," said Rodney Ewing, Stanford geologist and co-author of the paper published Feb. 21 in the journal Science Advances, to phys.org.
Of course, this isn't the first time scientists have synthesized diamonds from other materials (it's been done for 60 years). However, the process usually takes an exorbitant amount of energy, time, or the addition of a catalyst (usually a metal), and this diminishes the quality of the diamond. "We wanted to see just a clean system, in which a single substance transforms into pure diamond — without a catalyst," said Sulgiye Park, the study's lead author and postdoctoral research fellow at Stanford's School of Earth, energy & environmental sciences (Stanford Earth), reports phys.org.
The applications for this new transformation go beyond jewelry. Diamonds — known for their chemical stability, extreme hardness, optical transparency, and high thermal conductivity — are extremely valuable as a material for medicine, quantum computing technologies, industry, and biological sensing.
"If you can make even small amounts of this pure diamond, then you can dope it in controlled ways for specific applications," said Yu Lin, the study's senior author and staff scientist in the Stanford Institute for materials and energy sciences (SIMES) at SLAC National Accelerator Laboratory.
Recipe from the infernal depths
Diamonds naturally crystallize from carbon, hundreds of miles beneath the surface of the Earth. This is because — deep underground — temperatures climb to thousands of degrees Celsius (and Fahrenheit). When we dig up diamonds formed this way, we're collecting diamonds that have launched upward from the boiling depths during volcanic eruptions from millions of years ago, which carried ancient minerals from the interior of the planet with them.
This means diamonds can tell us something about what it's like inside the interior of Earth. "Diamonds are vessels for bringing back samples from the deepest parts of the Earth," said Wendy Mao, Stanford mineral physicist and leader of the lab where Park performed most of the experiments from the study.
The new process starts with three kinds of powder refined from tankers full of petroleum. "It's a tiny amount," said Mao to phys.org. "We use a needle to pick up a little bit to get it under a microscope for our experiments."
At first blush, the odorless, sticky powders seem similar to rock salt. But experienced scientists can use a powerful microscope to differentiate atoms arranged in the same spatial pattern as the ones that compose a diamond crystal. It's like an intricate cage of diamond was cut into smaller bits composed of one, two, or three smaller cages.
Diamonds — like fossil fuels — have a bad rap. In some cases, like global climate change, it seems deserved. But as this new technology advances, we might invert the adage that says "two wrongs don't make a right," and produce diamonds from fossil fuels without having to wait millions of years.