Bulk hexagonal diamond

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Bundy, F. P. & Kasper, J. S. Hexagonal diamond—a new form of carbon. J. Chem. Phys. 46, 3437–3446 (1967).

Frondel, C. & Marvin, U. B. Lonsdaleite, a hexagonal polymorph of diamond. Nature 214, 587–589 (1967).

Hanneman, R. E., Strong, H. M. & Bundy, F. P. Hexagonal diamonds in meteorites: implications. Science 155, 995–997 (1967).

Article ADS CAS PubMed Google Scholar

Pan, Z., Sun, H., Zhang, Y. & Chen, C. Harder than diamond: superior indentation strength of wurtzite BN and lonsdaleite. Phys. Rev. Lett. 102, 055503 (2009).

Qingkun, L., Yi, S., Zhiyuan, L. & Yu, Z. Lonsdaleite – a material stronger and stiffer than diamond. Scr. Mater. 65, 229–232 (2011).

Israde-Alcántara, I. et al. Evidence from central Mexico supporting the Younger Dryas extraterrestrial impact hypothesis. Proc. Natl Acad. Sci. USA 109, E738–E747 (2012).

Article PubMed PubMed Central Google Scholar

Tomkins, A. G. et al. Sequential lonsdaleite to diamond formation in ureilite meteorites via in situ chemical fluid/vapor deposition. Proc. Natl Acad. Sci. USA 119, e2208814119 (2022).

Endo, S., Idani, N., Oshima, R., Takano, K. J. & Wakatsuki, M. X-ray diffraction and transmission-electron microscopy of natural polycrystalline graphite recovered from high pressure. Phys. Rev. B 49, 22–27 (1994).

Isobe, F., Ohfuji, H., Sumiya, H. & Irifune, T. Nanolayered diamond sintered compact obtained by direct conversion from highly oriented graphite under high pressure and high temperature. J. Nanomater. 2013, 380165 (2013).

Guillou, C. L., Brunet, F., Irifune, T., Ohfuji, H. & Rouzaud, J.-N. Nanodiamond nucleation below 2273 K at 15 GPa from carbons with different structural organizations. Carbon 45, 636–648 (2007).

Shiell, T. B. et al. Nanocrystalline hexagonal diamond formed from glassy carbon. Sci. Rep. 6, 37232 (2016).

Article ADS CAS PubMed PubMed Central Google Scholar

McCulloch, D. G. et al. Investigation of room temperature formation of the ultra-hard nanocarbons diamond and lonsdaleite. Small 16, 2004695 (2020).

Erskine, D. J. & Nellis, W. J. Shock-induced martensitic phase transformation of oriented graphite to diamond. Nature 349, 317–319 (1991).

Kurdyumov, A. V., Britun, V. F., Yarosh, V. V., Danilenko, A. I. & Zelyavskii, V. B. The influence of the shock compression conditions on the graphite transformations into lonsdaleite and diamond. J. Superhard Mater. 34, 19–27 (2012).

Kraus, D. et al. Nanosecond formation of diamond and lonsdaleite by shock compression of graphite. Nat. Commun. 7, 10970 (2016).

Turneaure, S. J., Sharma, S. M., Volz, T. J., Winey, J. M. & Gupta, Y. M. Transformation of shock-compressed graphite to hexagonal diamond in nanoseconds. Sci. Adv. 3, eaao3561 (2017).

Armstrong, M. R. et al. Highly ordered graphite (HOPG) to hexagonal diamond (lonsdaleite) phase transition observed on picosecond time scales using ultrafast x-ray diffraction. J. Appl. Phys. 132, 055901 (2022).

Németh, P. et al. Lonsdaleite is faulted and twinned cubic diamond and does not exist as a discrete material. Nat. Commun. 5, 5447 (2014).

Nakamuta, Y. & Toh, S. Transformation of graphite to lonsdaleite and diamond in the Goalpara ureilite directly observed by TEM. Am. Mineral. 98, 574–581 (2013).

Németh, P. & Garvie, L. A. J. Questionable lonsdaleite identification in ureilite meteorites. Proc. Natl Acad. Sci. USA 120, e2304890120 (2023).

Németh, P. et al. Complex nanostructures in diamond. Nat. Mater. 19, 1126–1131 (2020).

Németh, P. et al. Shock-formed carbon materials with intergrown sp3- and sp2-bonded nanostructured units. Proc. Natl Acad. Sci. USA 119, e2203672119 (2022).

Yang, X. et al. Centimeter-sized diamond composites with high electrical conductivity and hardness. Proc. Natl Acad. Sci. USA 121, e2316580121 (2024).

Article CAS PubMed PubMed Central Google Scholar

Salzmann, C. G., Murray, B. J. & Shephard, J. J. Extent of stacking disorder in diamond. Diam. Relat. Mater. 59, 69–72 (2015).

Irifune, T. et al. Formation of pure polycrystalline diamond by direct conversion of graphite at high pressure and high temperature. Phys. Earth Planet. Inter. 143–144, 593–600 (2004).

Bundy, F. P. et al. The pressure-temperature phase and transformation diagram for carbon; updated through 1994. Carbon 34, 141–153 (1996).

Niwase, K. et al. Quenchable compressed graphite synthesized from neutron-irradiated highly oriented pyrolytic graphite in high pressure treatment at 1500 °C. J. Appl. Phys. 123, 161577 (2018).

Luo, K. et al. Coherent interfaces govern direct transformation from graphite to diamond. Nature 607, 486–491 (2022).

Sumiya, H., Irifune, T., Kurio, A., Sakamoto, S. & Inoue, T. Microstructure features of polycrystalline diamond synthesized directly from graphite under static high pressure. J. Mater. Sci. 39, 445–450 (2004).

Sumiya, H., Yusa, H., Inoue, T., Ofuji, H. & Irifune, T. Conditions and mechanism of formation of nano-polycrystalline diamonds on direct transformation from graphite and non-graphitic carbon at high pressure and temperature. High Press. Res. 26, 63–69 (2006).

Honda, S. et al. In situ observation of transformation of neutron-irradiated highly oriented pyrolytic graphite (HOPG) by X-ray diffraction under high-pressure and high-temperature treatment. Jpn. J. Appl. Phys. 60, 095002 (2021).

Fan, Z. et al. GPUMD: a package for constructing accurate machine-learned potentials and performing highly efficient atomistic simulations. J. Chem. Phys. 157, 114801 (2022).

Shi, J. et al. Double-shock compression pathways from diamond to BC8 carbon. Phys. Rev. Lett. 131, 146101 (2023).

Pan, S. et al. Shock compression pathways to pyrite silica from machine learning simulations. Phys. Rev. B 110, 224101 (2024).

Feng, X. et al. Nanosecond structural evolution in shocked coesite. Sci. Adv. 11, eads3139 (2025).