Chinese scientists have created what they say is the first pure sample of a rare type of diamond called hexagonal diamond. Scientists had predicted this special form of diamond many years ago, and it has sometimes been found in meteorites that came from broken dwarf planets. This new research may finally prove that the material truly exists.
Normal diamonds, also known as cubic diamonds, are considered the hardest natural material on Earth. The Mohs hardness scale, which measures how resistant minerals are to scratching, even uses diamond as the highest point on the scale. Cubic diamonds get their name from the way their carbon atoms are arranged in a cube-like structure.
Hexagonal diamond is different. In this form, the carbon atoms are arranged in a hexagonal pattern, similar to a honeycomb. Because of this different structure, scientists believe hexagonal diamond could be even stronger than regular diamond.
The idea of hexagonal diamond was first suggested in 1962 by researchers at the Pittsburg Coal Research Center. They believed that carbon atoms in diamonds could form a hexagonal structure instead of the usual cubic one. In 1967, scientists reported finding this material in the laboratory and named it lonsdaleite. Later, researchers also found traces of it in special meteorites called ureilites, which come from the interior of shattered dwarf planets.
Hexagonal Diamond
One famous example came from the Canyon Diablo meteorite, which created the Barringer Crater in Arizona. Some pieces of this meteorite were found to contain a mix of cubic and hexagonal diamond. However, not all scientists agreed with these findings. Some believed the evidence might actually be damaged cubic diamonds arranged in unusual ways.
One major difficulty in studying hexagonal diamond has been the lack of pure samples. Most of the time it appears mixed with cubic diamond, graphite, and other minerals, making it very hard to measure its true properties.
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In a new study published on March 4 in the journal Nature, researchers solved this problem by creating several pure hexagonal diamond samples about 1.5 millimeters wide. These samples were large enough for scientists to properly test their properties.
The team discovered that hexagonal diamond is stiffer, harder, and more resistant to oxidation than normal diamond. This means it can handle much higher temperatures without reacting with oxygen. Because of this ability, it could be very useful for industrial tools such as drilling equipment and cutting tools.
To create the material, scientists compressed highly ordered graphite for 10 hours under extremely high pressure of about 20 gigapascals, which is around 200,000 times Earth’s normal atmospheric pressure. The material was also heated to temperatures between 1,300°C and 1,900°C. Under these extreme conditions, the graphite transformed into hexagonal diamond. However, at even higher pressure and temperature, it started turning into normal cubic diamond again.
The study also gives strong evidence that hexagonal diamond is a real material. Scientists confirmed its structure using detailed analysis and computer simulations.
Hexagonal diamond could have many important uses in the future. It may improve cutting and drilling tools, polishing materials, and heat-management systems in electronics. It may also help scientists understand how certain meteorites formed and provide new clues about the history of our solar system.
Researchers say their method could allow the production of larger amounts of hexagonal diamond in the future. If that happens, this extremely strong material could open new possibilities in science and industry.
Source: livescience.com
