Secrets from the Depths of Space and Earth: Unraveling Newly Discovered High-Pressure Polymorphs in Meteorites and Diamond Inclusions

Significant recent discoveries of a large group of high-pressure (HP) minerals are reviewed. These minerals can be classified into two genetic types: those formed in shocked meteorites and impact craters and those formed under static P-T conditions and found as inclusions in diamonds. Of particular interest are the HP-polymorphic modifications of minerals such as olivine, ilmenite, ulvöspinel, wollastonite, and feldspars. Some examples include asimowite, poirierite, ohtaniite, liuite, wangdaodeite, tschaunerite, breyite, davemaoite, lingunite, and liebermannite. Special attention is also devoted to new dense hydrous silicates, which show much better stability than other known hydrous minerals to act as water reservoirs in the early stage of Earth’s geological history. The crystal structures and compositions of these new HP-minerals provide valuable insights into the complex petrology of deep geospheres, otherwise not obtainable in laboratory experiments. Using such a rich database, further steps became appropriate and possible toward the directions of a more advanced knowledge of evolution, composition, and structure of Earth.