Meteorites exposed to high pressures and temperatures during impact-induced shock often contain minerals whose occurrence and stability normally confine them to the deeper portions of Earth’s mantle. One exception has been MgSiO ₃ in the perovskite structure, which is the most abundant solid phase in Earth. Here we report the discovery of this important phase as a mineral in the Tenham L6 chondrite and approved by the International Mineralogical Association (specimen IMA 2014-017). MgSiO ₃ -perovskite is now called bridgmanite. The associated phase assemblage constrains peak shock conditions to ~ 24 gigapascals and 2300 kelvin. The discovery concludes a half century of efforts to find, identify, and characterize a natural specimen of this important mineral.

Encapsulating Earth's deep water filter: Small inclusions in diamonds brought up from the mantle provide valuable clues to the mineralogy and chemistry of parts of Earth that we cannot otherwise sample. Tschauner et al. found inclusions of the high-pressure form of water called ice-VII in diamonds sourced from between 410 and 660 km depth, the part of the mantle known as the transition zone. The transition zone is a region where the stable minerals have high water storage capacity. The inclusions suggest that local aqueous pockets form at the transition zone boundary owing to the release of chemically bound water as rock cycles in and out of this region. Science , this issue p. 1136

Lower mantle “garbage can”: Calcium silicate perovskite has finally been identified in a natural sample and now has the mineral name davemaoite. Tschauner et al . discovered the type mineral trapped at high pressure and temperature as a diamond inclusion (see the Perspective by Fei). Structural and chemical analysis of the mineral showed that it is able to host a wide variety of elements, not unlike fitting bulky objects into garbage can. Specifically, it has a large amount of trapped potassium. Davemaoite can thus host three of the major heat-producing elements (uranium and thorium were previously shown experimentally) affecting heat generation in Earth’s lower mantle. —BG

In this paper, we discuss the occurrence of liebermannite (IMA 2013‐128), KAlSi₃O₈, a new, shock‐generated, high‐pressure tetragonal hollandite‐type structure silicate mineral, in the Zagami basaltic shergottite meteorite. Liebermannite crystallizes in space group I4/m with Z = 2, cell dimensions of a = 9.15 ± 0.14 (1σ) Å, c = 2.74 ± 0.13 Å, and a cell volume of 229 ± 19 ų (for the type material), as revealed by synchrotron diffraction. In Zagami, liebermannite likely formed via solid‐state transformation of primary igneous K‐feldspar during an impact event that achieved pressures of ~20 GPa or more. The mineral name is in honor of Robert C. Liebermann, a high‐pressure mineral physicist at Stony Brook University, New York, USA.

This paper describes riesite, a new high-pressure polymorph of TiO₂ from the Ries impact structure, Germany. Riesite occurs in shock-induced melt veins within xenoliths of bedrock in suevite. It is structurally closely related to srilankite from which it differs by having two distinct cation sites rather than one and through its monoclinic symmetry. It is indicative that riesite forms only upon release from the shock state upon back transformation from akaogiite.