Experimental Etching of Diamonds: Extrapolation to Impact Diamonds from the Popigai Crater (Russia)

Diamond etching in high-temperature ambient-pressure experiments has been performed aimed to assess possible postimpact effects on diamonds impact craters, for the case of Popigai crater Yakutia (Russia). The with different etchants, including various combinations silicate melts, air, and inert gases, demonstrated diversity microstructures {111} diamond faces: negative or positive trigons, as well hexagonal, round, irregularly shaped etch pits striation. surface features obtained after kimberlitic are similar those observed natural some difference due origin latter a result martensitic transformation graphite target rocks. Extrapolated diamonds, experimental results lead several inferences: (1) crystals experienced oxidation graphitization during pressure decrease event, while molten rocks remained at high temperatures. (2) Natural melts is large range states controlled by O2 diffusion. (3) Impact near oxidized highest rates, whereas within melt were shielded from oxidizing agents unchanged.