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Chinese physicists at Zhengzhou University have synthesized the first pure, millimeter-sized samples of hexagonal diamond — also known as lonsdaleite — by crushing graphite at 200,000 times atmospheric pressure, producing a material that clocks in at 114 gigapascals on the Vickers hardness scale compared to natural diamond's 110 GPa. The achievement, published in Nature, resolves nearly six decades of scientific controversy over whether hexagonal diamond exists as a distinct material or is merely defective cubic diamond, and opens the door to potential applications in cutting tools, thermal management, and quantum sensing.