Comparative Characteristics of Impact Diamonds of the Popigai Astrobleme and Synthetic Diamonds Produced by Explosion

The paper presents the characteristics of impact diamonds from the Popigai meteorite crater, formed by martensite transformation of graphite-bearing gneisses due to meteorite impacts. These diamonds have a nanopolycrystalline structure and consist of two phases, i.e., cubic (diamond) and hexagonal (lonsdaleite). They are distinguished by phenomenal abrasion resistance, on average twice as high as the abrasion resistance of single-crystalline diamonds. The work considers the possibility of producing similar diamonds by explosion. It is noted that diamonds, which are most similar in structure, are produced through exploding a composition of graphite and hexogen; lonsdaleite is present in the material obtained in this way. However, in any case, diamonds produced by explosion are very small in size, incomparable with natural ones.