China Just Made An Artificial Diamond That's Harder Than Natural Alternatives

Diamonds don't just make for beautiful jewelry and iconic James Bond titles. They're also among the strongest minerals on the planet. Emphasis belongs on the word "among," because until recently, scientists believed that the diamond's strength among Earth minerals was unmatched. However, the discovery of lonsdaleite, also known as hexagonal diamond, changed that. Now, a team in China claims to have synthesized lonsdaleite, creating a diamond whose hardness and strength could rival that of diamonds typically found on Earth.

A few years ago, scientists discovered lonsdaleite in meteorite samples from Africa, and it wasn't the first time researchers had come across this mineral around a meteor strike. In the past, however, researchers had only discovered relatively small quantities of lonsdaleite. The lonsdaleite recently found in Africa included crystals that may be approximately 1,000 times the size of the those found in earlier discoveries. Such finds have confirmed that hexagonal diamond exists at least somewhere in the universe. 

Now, in a paper in the journal Nature, researchers in China describe how they've synthesized lonsdaleite in a lab. Although this isn't exactly the first time scientists have artificially created a substance or material that rivals the strength and hardness of diamonds, it likely does represent the first time researchers have created this particular material in this particular unique manner.

The authors of the study explain how, historically, attempts to study the structure of hexagonal diamond have proven limited. This is partially because previous methods of synthesizing hexagonal diamond have resulted in the samples being destroyed. Often, any quantities of hexagonal diamond that have been available for study have been mixed with other materials that render direct examination and analysis of lonsdaleite difficult or impossible.

The Chinese research team behind the study successfully synthesized hexagonal diamond via a method that addresses these limitations. The method involves compressing highly oriented graphite at high temperatures. For instance, the team synthesized quantities of hexagonal diamond by exposing nanometer sheets of graphite to 20 gigapascals of pressure at temperatures of 1,300 degrees Celsius. By comparison, the atmospheric pressure at sea level is about 100 kilopascals. The pressure the researchers applied to synthesize hexagonal diamond is equal to about 200,000 times that.

This achievement provided the team the opportunity to perform tests confirming lonsdaleite is stronger than other common forms of diamond on our planet. If hexagonal diamond can be synthesized in bulk quantities in the future, it may have various practical applications. Its strength makes it potentially ideal for industrial cutting tools, while its ability to conduct heat and withstand damage could be useful in electronics. Such innovations serve as reminders that materials and minerals that literally fall from the sky can inspire breakthroughs on Earth.